They did this with Force Unleashed and now it looks like Killzone and GOW3.
Picking up Resistance 2 (paid in full, btw):
GS: Ok, I'm going to put your deposit down on God of War for you.
Me: Um, no. Don't want it.
GS: Ok, then I'll just put you down for Killzone. That's going to be the best game on any system next year.
Me: No, don't want it. Just want to pick up my game.
GS: Fine, you won't be able to buy a copy then since it'll be sold out. (says the guy standing in front of about 10 Resistance 2 LEs and three times that many regular copies; none of which are reserved).