"Sgt. David Martinez with the San Diego County Sheriff's Dept. said it's legal to own a cannon but is not necessarily legal to fire it."
for me it's pretty much the same as with pit bulls. No it's not the cannon's fault, nor is it the pit bull's fault, but they're both dangerous and we might want to think about making them illegal, or at least finding a way to keep them out of the hands of morons.