Dude. Putting any kind of weaponry payload on a civilian aircraft (RC or otherwise) is highly, highly illegal in the US. I'm sure it's illegal practically everywhere else that's sane for the exact same reasons.
It's not just "remote hunting" that's banned. It's the attachment of any weapon to an aerial or moving platform that's banned. A slingshot on a paper plane would qualify by a literal interpretation of the laws as written.
Do you have a source for this? It sounds quite likely, but any time law gets discussed I always try to find the relevant texts. I'm having trouble finding anything other than laws about carrying firearms on your person while on a commercial airliner.
See section 91.15 for the part about "dropping of items."
I'm still looking for the BATF regs on this. IANAL, so it's a bit of work, but I do know a few guys that do weapons systems (govt contractor) and my younger brother is a pilot.
It's not just "remote hunting" that's banned. It's the attachment of any weapon to an aerial or moving platform that's banned. A slingshot on a paper plane would qualify by a literal interpretation of the laws as written.