Ed, I wouldn't be so quick to say it's too restrictive. I think there are very good reasons for not allowing such weapons to be bought by the average citizen. I won't say whether or not they should be allowed but I can see where allowing just anyone to get such a weapon could make for some dangerous situations. Just imagine if you use a tazer on a loose dog and the dog's owner happens to have a tazer him/herself. You end up getting tazed. What if the person hasn't been properly trained in its use? Stun guns or tazers, used improperly, can kill.
I'm sure a tazer or other such device would teach dogs to not chase again if it doesn't kill them. So does pepper spray and, while it can be very painful, at least it's not deadly when not used properly. It's also easier to carry with you when running.
Ed, I didn't mean for my story to prompt some form of vigilante justice or strike fear in the heart of everyone who reads it. I just want to encourage people to ensure that laws that are in place for the safety of everyone are enforced by contacting the officials who can make sure they are enforced. If you are concerned about loose dogs, get some pepper spray. I've seen how well it can work to keep dogs at bay.