Who should decide the difference?
Most of our statutes are very sloppily written. (Common Whore grads)
Put it this way: Out of 25 million views, how many wise guys are going to decide to do this at home, with say, some pipe and stuff and a 12 gauge shell with the shot removed, and then some kid gets a charge of glitter in his eyes. I hope such a thing would never happen, but to answer your question, a jury.
That's who decides the difference. That's why it's not gonna happen at my house, and that's why I'm admittedly a stickinthemud about it and that's why I'm really kinda shocked at the indifference I see about it.
It's all fun and games until someone gets maimed for life.
Then it goes to a jury. Since you asked.