But really,
Why throw candy at trick or treaters to begin with? If you shoot it out of a potato gun, no one will likely come back year after year. If you dont want to give candy, then leave the porch light off and or ignore the knocks. Chances are the 'word' on the street will be, dont go to that guys house!
If you invite people to your house, suchs as TOT's, then shoot them with a potato gun full of candy, then you open yourself up to assault because they didnt tresspass, you invited them with honsest intentions. I'll bet if you shoot a kid with a potato gun, you'll get a visit from local/county police within minutes and maybe some street justice!
Fordman