Unless I'm wildly misreading this blog post, TF2 has now dipped to shady Korean MMO levels of "pay us an uncapped amount of money" tactics:
The Per Diem Perk
Mister Reddy has prepared three absolutely unique one-of-a-kind hats that will rotate through the mercenary community every day. Who will get them? The three mercs who give the most gifts, win the most duels, and purchase the most map stamps on a given day. Presumably wearing these one-of-a-kind hats will make the winners feel like they've achieved something. Or not, I could give a damn. So long as they make you all better killing machines.
As someone who gets back into TF2 once every few months, I've never been an active enough player to buy anything from the shop (I did pay $8 for that Japanese tsunami charity hat), but this tactic seems like a brand new low that really milks the few hundred players who have no self-control when it comes to their disposable income.