Kids will do stuff on their own. You cant blame the parents for that. Hell my little brother came home with an expensive looking Minecraft Guide (very popular game among little kids right now). I asked him where he got it. He said some girl in his class gave it to him. Asked if he traded her anything for it. He said 2 markers. (this is where I frowned) Was able to eventually deduce that HE was the one that initiated the trading process, not her and that either she was banished from using markers or she had a crush on him. Now my brother is a good, mostly honest kid but little kids will trick people for what they really, really want. And a replica gun is really, really cool. You cant blame the parents for this one at all. BTW i made my brother give the Guidebook back to the lil girl.
The cop is really the only person to blame.