Of course we can turn this around on them. If they ask about guns, ask them back. If they respond that they don't have a gun, then tell them you will not let your child play over there, because there is no way for the parents to protect the children if an intruder breaks in.
If it gets to the point where the police are called because someone reports a gun, then just find your local anti-gunners and call the police on them. That should go over really well.
Knock, Knock, Police: I have a report that you pointed a gun at someone. Anti-gunner: No way, what are you talking about, there is no gun in this house. Police: sure there isn't, mind if I look around? Anti-gunner: yes I do, you can't come in my house. Police: I need back and a K-9 unit.