Are they teaching kids how to get themselves killed?
Choice A(the "wrong" choice):
Play cool and say, "Oh, yeah-that’s pretty cool."
Choice B(the "right" choice):
Say, "Hey man, we don’t play with guns. We’re outta here." They leave, finding an adult to tell them that the other kids have a gun.
Yeah, tattle on some armed punk(within earshot, judging by the picture), great idea. Maybe they should moon the armed kids, give them the finger, and then spit in their faces. That's a good idea too. Show them how much you don't like guns.