For some reason people don't believe me that if I ever caught one of my dogs biting someone in my presence on my property that didn't need to be bit, I'd put the dog down, there on the spot. Can't remember ever owning a dog that "went" after someone.
If anything they (the dogs) can drive me nuts when they hear someone in the driveway. That said, that's what they're supposed to do anyways LOL
Your dog, your responsibility. A dog that bites or acts aggressive towards humans off the dogs "turf" is a disaster waiting to happen. It's not a question of "if", but "when".
That said, we have people who apparently can't control their dogs and their own adult children. If a 26 year old is playing with the OP's mailbox, tells you enough about the parents.