Good ol' ASC over-panic.
Cops should of confinscated it. I'd tell him to not use it in a public place, and also advise him on what can happen if he doesn't handle himself right when a cop shows up. Possibly notify the police if he does something really stupid that could put him in harms way.
These kids were doing nothing wrong, the possibility of harm is near zero (in this case), you all take this shit too seriously. See Lisa's post