| DMDark |
Inter-party violence is something that I personally find to be one of the best things about tabletop sessions. Though when it's done completely randomly then it certainly loses it's flavour. One of the groups I've been in has equally erratic behaviour and overall silliness, this is with 'adults' though. Eventually one of the more serious RPers will step in and the threat that an interparty fight can happen is what is needed. I've played a character that lost his nerve and killed a player character continually hindered the party and lead to the death of innocents. The DM allowed it and I was grateful, said person rage quit the group too.
I think with kids its especially hard and giving them the same freedom as you would with a more experienced player is perhaps a mistake, but then why let them play? If they're going to play they should play. Just make the consequences more sever. Attacking a statue with a great sword? Oh no, you damaged your sword as its now blunt and does -2 damage. Destroyed the chest of it was full of alchemist fire, your on fire now and punching hard stone, take 1D4 damage + your own strength modifier. If they wish to continue playing that way then they will eventually die, which isn't fun in a one off but you dont rent out a game to find out about how fast you can die by doing stupid stuff.
Another way is asking why? If this person is roleplaying make them explain their characters reasoning, if it isn't good enough. either disallow or remove a small amount of xp.