The only people I know of is animal control, and I don't think they do much. I know our neighbors have had them called on their labs before. They let them run all over the place and 1 is extremely aggressive. When he jumped into an open truck door of a worker at another neighbors house and wouldn't let the truck owner in I know that neighbor called animal control. I don't know what happened, only that they still have the dogs and their still running loose.

As to the laws, I always thought that if your dog is on leash and the other is off in an area that has leash laws then your not held responsible, but come to think of it I've never actually checked. Hopefully it will never come up, but I'll check for my own peace of mind.