BB gun — that's as in "ball bearing" — also known as "airsoft".

In this example, crossfire would require someone to walk into an airsoft combat area without any eye protection and for someone in that game to not realise and shoot them anyway. In the face.

Stray BB bullets don't go very far. They're not rifled, and they have fairly low muzzle energy compared to real weapons — I've shot myself with one at zero range, and even on bare skin it stings rather than penetrates.

A bb gun and an airsoft gun are very different things to me. A bb gun shoots metal balls and airsoft shoots plastic. I would not want to be hit by a bb gun, but an airsoft gun is no big deal (though the snipers can definitely hurt).