I own a very driven terrier-type dog and I would never be stupid enough to let him off leash in an area where, say....a squirrel might run by. It would be sheer idiocy on my part to do something like that, to put him a position where he is bound to fail.

When I've seen dogs get into it at the park, the best solution I've seen (if the owners don't have control) is to grab them by their hand legs and drag them away from the action. Sure works better that trying to BEAT a dog into submission.

No, Staffs are not all aggressive, and almost never are they "vicious". Any breed can bite, maim, or kill a person.