They are trying to put this into the context of cheaters in Las Vegas who can be eXx1l3d from casinos because they are, in the long run, making more money while the casinos are losing money.  The problem is exactly that, though: Gamestop is still making money from those hackers and PSP CFW users who want to enjoy their PSP as much as possible.  There is nothing the hackers can do to take money from the store, except by using ISOs, but that isn't actually taking the money from the store, since the store will still have whatever copy you didn't buy from them.  Just show your disapproval of the hacker, and let him shop.  Don't be a douche -.-

In fact, they should be honored that a hacker would want to buy from their store, with the huge prices they have at Gamestop compared to on-line stores and even many Walmarts.  You can pay easily half for most accessories and often times much less by going on-line, but whatever.