"Scalp a Ticket" vs "Resell a Ticket"

Solution 1:

To scalp carries an informal, possibly illegal (unauthorised) , connotation that resell does not:

  • (Informal.) to resell (tickets, merchandise, etc.) at higher than the official rates.

Thus usage is from the late 19th century from a practice that became popular in the U.S. with long distance train tickets:

Scalp: (Etymonline)

  • Meaning "person who re-sells tickets at unauthorized prices for a profit," 1869, American English;earliest reference is to theater tickets, but often used late 19c. of brokers who sold unused portions of railway tickets.

    • [Railways charged less per mile for longer-distance tickets; therefore someone travelling from New York to Chicago could buy a ticket all the way to San Francisco, get out at Chicago and sell it to a scalper, and come away with more money than if he had simply bought a ticket to Chicago; the Chicago scalper would hold the ticket till he found someone looking for a ticket to San Francisco, then sell it to him at a slight advance, but for less than the official price.]
  • Perhaps from scalp (v.); scalper was a generic term for "con man, cheater" in late 19c. Or perhaps the connecting sense is the bounty offered for scalps of certain destructive animals (attested in New England from 1703) and sometimes Indians (i.e., having only part of something, but still getting paid). Some, though, see a connection rather to scalpel, the surgical instrument.

Scalping in finance:

  • A trading strategy that attempts to make many profits on small price changes. Traders who implement this strategy will place anywhere from 10 to a couple hundred trades in a single day in the belief that small moves in stock price are easier to catch than large ones.

  • Traders who implement this strategy are known as scalpers. The main goal is to buy (or sell) a number of shares at the bid (or ask) price and then quickly sell them a few cents higher (or lower) for a profit. Many small profits can easily compound into large gains if a strict exit strategy is used to prevent large losses.

(Investment.com)

Solution 2:

"Scalp", as a verb, is a common (though less so over time (*)) usage in the US. In general (when not meaning to physically relieve someone of their hair, if only in a barber shop) it means to sell something at an exorbitant price (or buy something at an artificially low price), under some situation where the other party has little choice. (Eg, "We got scalped on that hotel room, but it was the only one left in town." Or, "I got scalped selling the house, but I needed the money.")

The reference clearly is to the historical practice of some Native American tribes to take the scalps of their fallen adversaries as battle trophies. As I understand it, this was usually done when the victim was dead, but occasionally while still alive, and would have been excruciatingly painful to the live victim.

(*) Likely "scalp" in the sense of reselling tickets for profit will continue to be used, but it's use for the more general case seems to be diminishing.

Solution 3:

My answer is only to the question

Does "to scalp" have a stronger connotation of "illegality" than "to resell"?

It's not just a stronger connotation, but rather that the illegality is the defining difference between scalping and reselling.

Reselling generally is perfectly legal. If it wasn't, there would be no supermarkets, no Craigslist, no eBay.

For certain goods - primarily for tickets - there are restrictions on who can resell, and for what price. The reasoning is that unlike most types of goods, tickets for events are both limited in number (in the relevant cases, dramatically less than the demand), and time sensitive. Unlike eggs or purses or skis, with tickets, once they are gone, they are gone, and once the event has passed, they have no value.

When a few people (the scalpers) buy large numbers of such tickets, they further exacerbate the scarcity of the tickets, thus driving up prices further.

Basically, scalping more similar to stock market manipulation, or Enron's activities, than to reselling.