Originally Posted by Gryphon
If the authorities know very specifically what's going on it's usually given the ok. I'd recommend checking with them first before purchasing anything. Depending on your location you may also need to advise air traffic control or the marine authorities. It sounds like a big hassle but really it's as simple as a phone call. Rather than trying to explain what airsoft is, tell them you're paintballing. Everyone knows what that is.
Or you could always ask for blue smoke, insted of orange. But i dont know how that would be done.
But it would be neat.