I think we should however give some simple warnings, politely explain the them that we would appreciate it if they would exit game to trade or go elsewhere that does not mind it.
Yeah, between an AFK manager, in-game messages, and a polite admin from time to time, trade spamming should be handled appropriately. Just a simple "easy on the trading guys, not during the game please"
Can we start an e-bay trading. $.75 per trade. Help make some money here for the servers. That would be great.
Ha - yeah!
From what I read, apparently there are a lot of scams and underhanded marketing related to this too. This kind of thing has always existed for MMO games, but never for TF2 until now.
Honestly, mixing real money and an online game is problematic and I'm very sure Valve acutely realizes this and predicted this kind of thing before even considering an implementation.
And there are numerous protections against fraud and scams, in fact I've heard they even have protection for users who buy too much at once as that might be a stolen card.
They're doing a lot, but it can never be enough.