simply man up and even though you might get ostracized for a bit do the right thing anyway. tell the cops, tell the parents anything to stop this. 2 reasons come to my mind:
1. cops show up and kill the kids
2. airsoft gets a bad name and gets banned in canada (extreme i know but still)
even though your friends might hate you for it, do it anyway. cause trust me, if they want to play when they are older, and words gets out it was these kids who did this, they will:
a) never be allowed to play anywhere with any of us
b) i wouldn't be surprised if they get roughed up a bit for being so dumb.