Gillman I understand what you are saying but you don't know my grandmother, she used to be a badass MF'er in her day (and still is). As far as big dogs she (and my grandfather) have owned the gamut from pit bulls, rotts, etc. She goes on daily walks around the neighborhood for exercise and she has yet to be phased by all the big breeds that are out there.
Anyway the owner pretty much told her that he didn't raise his dogs to be that way and this aggressive behavior had only started once he moved next door. He mentioned that if the behavior persisted that putting the dog down would become an option but my grandma said she would probably beat him to it.
If OC spray is a more sound option (legally) I would even recommend that.