Sorry, Californians. It's a "NO-NO" for you. Probably a few other states also.
http://throwflame.com/products/flamethrower/
Nothing like a blazing roof and exterior of the walls to encourage someone to evacuate a premises. (Come on out and join the party.) Problem here is, it's only good for about 50 feet, using their recommended mix of 90% diesel and 10% gasoline (in those cases where you can't score your own napalm).