I would argue that slickdeals is certainly more used then this site in general. But it’s very unlikely someone from GameStop is watching any forums to look for exploiting glitches to jump on and stomp. It’s much more likely they have a mediocre program that watches the online transactions and assigns someone to look at whatever the computer flags as a potential issue.
The more surprising thing is that people do these flips for $5-10 store credit per game, to a maximum of however many trades of the same copy per account without being trade banned. Taking home a salary of $34 an hour while working AT home means I can literally take a nap or off on these forums, and I don't really get paid that much for IT.
Agreed that the poster pre-order bonuses suck. It'd be nice to have something interesting be included, but I suppose the manufacturing costs on small posters are negligible for a recovering GS.