Do Fireteam Medallions stack?

Fireteam medallions add a boost to experience and raise the chance to get loot. They are also active for everyone in your fireteam. But does having multiple active in your fireteam lead to better results/stacked boost.

Judging an increase in loot drops is difficult to determine and can simply be luck, so evidence of XP increase (or not) will be enough proof.

I used to think they stacked but after reading this article from Polygon and checking it out for myself it would seem that they do not stack.

(Bold emphasis mine)

"A Fireteam Medallion applies its buff to the entire fireteam. That buff sticks to you when you activate the medallion, and you can see the four-hour duration counting down. When someone else in your fireteam has activated one, you get the same buff — but you lose it if they leave the fireteam."

"If you have used a medallion and one of your teammates has also used a medallion, you will see both buffs on your character screen. As a result, many players believe that the buff for using a Fireteam Medallion yourself and the buff for being in a fireteam with someone else who has used one are separate buffs that stack."

"This probably isn’t true. I received the same amount of experience for completing a heroic Public Event alone with a medallion active that I did when I was in a fireteam with a player who also had one. It’s difficult to tell the impact of these buffs on loot, but it didn’t seem to be raining purple and gold when I had both buffs, and I gained no extra experience for having both buffs rolling. So I see no evidence to suggest these buffs have a stacking effect."

Information about the medallion's worth:

"What we can be reasonably sure of is the experience difference: Heroic Public Events with no medallion active award around 2,750 XP. I got about 3,375 XP — an extra 625 XP, or 22.7 percent — when using the medallion. That means that my Fireteam Medallion generated a marginal 17,500 XP over the course of 28 events."