Some of posts in this thread truly scare me.

1. Installing 3rd party software on the iPhone is not vandalism, they did not damage the phones. I hardly doubt "vandalism" would hold up in court.
Either way:
2. The manager forcing them to come back into the store and stay there falls under kidnapping and false imprisonment laws. This goes the same for things like shoplifting. If you are detained for shoplifting and did not actually shoplift, you can sue the pants off (and win) against the store for false imprisonment. If you did shoplift, various State merchant laws protect the merchant during special cases like shoplifting. If anyone (security, manager, etc) touches you while you leave (yes, just touches) even if you did something (shoplifted, vandalized), that is instantly battery and possibly assault. Very few States actually have laws that protect merchants from prosecution for assault & battery.
3. The kids should of kept walking away, they obviously did not know their rights. If the manager touched them, the kids could of had their parents sue for assault and battery. If the manager called the police, the police wouldn't do anything to the kids, as they did not violate any laws.
4. Obviously the manager was intimidating enough to get them to come back to the store instead of running away. The parents should sue Apple for false imprisonment and/or kidnapping depending on the State's definition of these offenses.