Now that users can jailbreak their iPhones through JailbreakMe without the use of a computer, some users are having fun with it. In this case, they are jailbreaking a floor model iPhone 4.
Though the phone can easily be restored by an Apple Store employee, it's still a bit of a jerk move. While many of us here at iSmashPhone own jailbroken devices, we don't know if doing it at the store is a nice thing to do. The devices are there so that people can see how they work. Plus, we aren't sure about the legalities of this since he is jailbreaking a unit that belongs to Apple.