How is this pathetic? Jailbreaking doesn't do anything to the device. It's a display model its not like i took some random guys touch and jailbroke. If bestbuy even noticed there being a cydia app now there all they would have to do is plug it in to a computer and hit restore. Give me a break.
There is probably paperwork involved as well, sounds like all you are doing is making an employee have to do a bunch of extra work. Don't you think the employees have enough to do without disconnect alarm sensors, unlocking the phones, plugging them into a computer, waiting out the restore from backup and filling out paperwork? Now multiply this a bunch of times as each inconsiderate "hacker" does the same. But if that's how you get your jollies then have at it.