Homemade grenade? is it allowed?

Well we were playing on MY private land couple days ago. My support gunner asked if he could bring one of his friends to play airsoft. Ok i said immediately but he's on the other squad. Well he shows up with homemade airsoft grenades. It's a firework mortar covered in 200+ aftermath bb's. In a ziploc bag covered with duct tape only exposing the wick. I took and threw it away for 3 reasons: 1. High explosive 2. I sure as heck don't want a fire on my land(dense vegetation and with this heat it is very dry!) 3. The last thing i want is the fire departant or something. But my question is the kid wants to play with us more and i'am thinking no but i want a second-hand opinion.

I wouldnt allow that kid back there unless you like confiscate the grenades and give em back after your done playing

You can let him play, but be sure he KNOWS that the pyrotechnics are a SERIOUS no-no.