Why are middlemen called “Junkets”?

Solution 1:

I've had the benefit(and pleasure) of reading the other answers. Here is a tangential supplement on etymology, which may provide some insight into the original word and the general context(also this) you refer to. Articles from the NED(late 19th):

Junket, sb. Forms: a. 4-7 ionket,(5 -ett, 6 -et(t)e), 6 ionckette, 6-7 iunket, 7-9 juncket, junkett, 7- junket. B. 6 ioncat, 6 iouncat, 6-7 iuncat, -cate, 7 iunkat, -kate, 7-8 juncate. See also JUNCADE. [Of somewhat obscure history, in respect to both of forms and senses, but app. a. ONF. * jonket, * jonquet, or jonquette, rush-basket, f. jonc rush, JUNK sb.1 Norman patois has 'jonquette' espèce de crème faite avec du lait bouilli, additionné de jaunes d'oeuf, de sucre et de caramel' (Moisy), and the related forms jonchée ( -med.L. juncata, It. giuncata) and jonchiere, jonquiere(:-*juncaria) are common in senses 1 and 2 of our word (see Littré and Godef.).

The B-forms in sense 2 may be directly from med.L. juncata (cf: JUNCADE); but their late occurence in sense 3 is notable. The history of sense 2 is not quite clear; and the relationship of 3 to 4 is complicated by the earlier JUNKERY.]

1. A basket (orig. made of rushes); esp. a basket in which fish are caught or carried. Now dial. [...]
2. A cream-cheese or other preparation of cream (orginally made in a rush-basket or served on a rush-mat; see JUNCADE); now, a dish consisting of curds sweetened and flavoured, served with a layer of scalded cream on the top. (Popularly associated with Devonshire, but answering to the 'curds and cream' of other districts.
3. Any dainty sweetmeat, cake or confection; a sweet dish[...] Obs.
4. A feast or banquet[...]; a picnic-party.

Juncade. Obs. rare1. [app. a. obs. F. joncade(in Rabelais), 'a certaine spoone-meet made of creame, Rose-water, and Sugar' (Cotgr.), a. Pr. joncada, cheese-curd, fresh cheese.] = JUNKET 2.

The Littré(mid-end 19th) overflows with meanings here, some related to rush:

Jonche: Terme de pêche. Ganse de corde qui sert à joindre plusieurs pièces de filet au bout l'une de l'autre. [fishing related]

Jonchère: Lieu couvert de joncs. Touffes de joncs qui se forment dans les étangs, dans les marais, et qui deviennent quelquefois des îles flottantes. [covered with rush, sometimes forming an isle]

Jonchée: [...] 3-Petit fromage fait dans un panier de jonc. Une jonchée de crème. [cheese in a rush-basket]

Jonchet: Nom de fiches longues et menues, dont quelques-unes portent des figures ; on fait tomber ce faisceau de fiches pêle-mêle sur une table, et, avec de petits crochets d'ivoire, il faut tirer adroitement le plus de fiches que l'on peut sans en faire remuer aucune autre. Jouer aux jonchets. Ce jonchet est un des miens. J'ai perdu un jonchet. [a game, this link contains an example where the term appears in a list with a card game and dominos]

As alluded to in the comments, there is also the boat with reference to chinese pinyin and cantonese pronunciation¹:

Jonque : Sorte de vaisseau fort en usage dans les Indes et à la Chine. Une jonque chinoise.

Éty. Espagn. et portug. junco, proprement navire, vaisseau ; anc. catal. incho ; ital. ionco ; vénit. zonco ; du chinois tchouen, bateau, vaisseau, prononcé à Canton chune suivant l'orthographe anglaise, c'est-à-dire en français tchoun.

Here's a related extract and note from the NED for Junk:

Junk, sb.3[...] [A word of Oriental origin, now adapted in most European langs.[...] App. adv. Javanese djong (occuring in compositions of 13th c. or earlier), 'ship, large vessel', Malay. adjong. The earlier English forms are from other European langs.

Some have sought the origin of the word in the Chinese ch'wan 'ship or sailing vessel'; but the Portuguese and Dutch were established in Java and the Malay Archipelago before they visited China, and found the Javanese and Malay word (wuch has no connexion with the Chinese) applied to all large native vessels as well as to the Chinese ships which visited those shores.]

A name for the common type of native sailing vessel in the Chinese seas. It is flat-bottomed, has a square prow, prominent stern, full stern, the rudder suspended, and carries lug-sails.

The name is now applied to Chinese, Japanese, Loochoo, Siamese, and other vessels of this type; early writers applied it still more widely to Malay, Javan, and even South Indian native vessels.

A fascinating nexus of meanings and diverse influences...

_{1. Offtopic and speculative, but I can't help noticing that the chinese word for guest is ke/ker.}

Solution 2:

Although The Economist article clearly uses junkets in the sense of “gambling trip facilitators,” this isn’t the only meaning that the term has. One (relatively) longstanding and common use of the term junket is to describe a some-expenses-paid trip to a casino—a meaning that seems not to have originated in a specifically Asian context. From Darwin Ortiz, Casino Gambling for the Clueless A Beginner’s Guide to Playing and Winning (1998) [combined snippets]:

Junket Requirements

My first advice to anyone considering going on a junket is to make absolutely certain he understands what is expected of him. Talk to the junket organizer and get the facts on all four of the casino's criteria. How much front money will be required? How much must you generate in markers? How long must you play and how much must you bet? Be equally specific in in determining exactly which of your expenses will be covered by the casino. As I pointed out earlier, there is tremendous variation in the package that different casinos offer to different players.

In Ortiz’s book, junket organizer seems to correspond to junket as used in The Economist. Lancelot Humble & Ken Cooper, The World’s Greatest Blackjack Book (1980) use the term junket agents rather than junket organizers for what appears to be the same profession:

While casino collection tactics may be controlled, the danger lies in running up a bad debt on a junket. A junket is a specially chartered trip to a casino at the expense of the casino. Junket agents arrange for groups of large bettors to take these complementary trips asking only that the gambler play at the sponsoring casino for a certain number of hours at a specified betting level. Junket agents whose clients are credit problems risk cancellation of their profitable junket trips. Once fired by a casino, the junket agent has little chance of getting dates at other casinos.

As used in the article from The Economist (of December 10, 2011), junkets appears to be a short form of junket organizers or junket agents—where junket refers to a contractual arrangement that includes an expenses-paid trip to a casino but that also imposes various requirements on the prospective gambler. This is essentially the answer that Spehro Pefhany offered back on May 5.

It’s a confusing usage, however, since junket continues to be used outside Macau (and the offices of The Economist) to refer to the trip itself (among other things), and since a third term—junket operators—is often used to describe, as one source puts it in a book published in 2005, people “who act as agents to take customers to casinos and extend them credit for gambling purposes.”

Complicating matters further, CLSA Asia-Pacific Markets, Macau Strategy: Market Outlook (April 25, 2008, pp. 5, 7) distinguishes between casino operators, junket operators, and junket agents:

As casino operators target more VIP business, junket operators will look to increase their commissions, narrowing margins for the casinos.

...

All six [casino] operators have their own casino property in place and they can compete on equal ground in the VIP segment as far as property is concerned. The determiners are junket commissions and working-capital facilitation. Junket operators bring VIP customers into the casinos and casinos typically work with a handful of junket operators or room operators who, in turn, run perhaps thousands of junkets on a full- or a part-time basis.

A key factor affecting junket operators’ choice of casino is their commission. The higher commission that casinos pay, the more incentive the junket operators have to bring customers to that property. A higher commission will also allow junket operators to rebate more to its agents, who can pass on more to their customers. Since the commission structure is tiered, it makes sense for a junket or junket operator to channel more of the business to one location, although it also needs to maintain gaming tables in multiple casinos to provide the customers a change of scene when needed. Perhaps a more important consideration here is working-capital facilitation. Junket operators typically have to prepay the casino for a certain number of non-negotiable chips. Junket agents in turn pay for chips, or obtain them on credit, for their share of these customers. The higher the customer volume, the more working capital will be required. If the junket operator can facilitate working capital for the [junket] agents, agents will be more eager to direct their customers towards the business interests of those junket operators.

Yet another complication is that junket can refer to the group of VIPs making the trip to the casino. Here is how Cathy Hsu, Casino Industry in Asia Pacific: Development, Operation, and Impact (2006) distinguishes between junkets and junket operators in a brief glossary:

junket: A group of players who travel to the casino specifically for the purpose of gaming. The travel is prearranged through a junket operator.

junket operator: The individual who is who is responsible for organizing junket trips. Usually an independent agent, who negotiates a commission for players of the junket group and is paid a commission based upon the actual mix of games.

Global Real Estate Center, Global Gaming Bulletin: 25th Anniversary Edition (2007, p. 125) corroborates Hsu’s usage as to junket, but prefers junket representative to junket operator:

Junket—A group of players who travel to a casino for the primary purpose of gambling at that casino. Often the cost of the food, lodging and transportation for these players is paid by the casino.

Junketeer—A player participating in a junket.

Junket Representative—The person responsible for organizing a junket. Also referred to as a Master.

In view of these complicated, highly technical, constantly evolving, and inconsistently applied gambling-industry terms, it seems very unwise of The Economist to have used junket to mean junket operator (or perhaps junket agent or junket representative or junket organizer). Generally, the more precise the term you use, the more likely you are to avoid having your meaning misinterpreted by uninitiated readers.

On a tangentially related note, I can’t resist pointing out the meanings that junket had in Samuel Johnson’s day. Here, as reproduced in E. L. McAdam & George Milne, Johnson’s Dictionary: A Modern Selection (1963) are Johnson’s 1755 definitions of the noun juncate and of the verb junket:

juncate. (1) Cheesecake; a kind of sweetmeat of curds and sugar. (2) Any delicacy. (3) A furtive or private entertainment. It is now improperly written junket in this sense, which alone remains much in use. See junket.

to junket. (1) To feast secretly; to make entertainments by stealth. [Example:] Whatever good bits you can pilfer in the day, save them to junket with your fellow servants at night. Swift.

So it seems that there has long been something surreptitious and ethically suspect about junkets.