I thought Efro's article was gross, but I also don't think this is bribery:
It's just valuing stuff differently because one person wants an invite and one person wants a booster box. Like, if players split and one gets the invite the other person definitely should get more of the other prizes.
This is pretty much the definition of bribery. Replacing a contest of skill with an economic transaction is what bribery and collusion is!