Sometimes I travel and my wife and I have discussed this same issue. If we need to hire people to mow the yard, we would have them do the front yard only. Strangers coming into the backyard is not an option at all. We were even told by the power company that the final push for them converting to the digital meters that can be read from the office, was our Cane Corso. Fact is, its not a good idea to put faith in a mastiff with a good temperament when it comes to the slight possibility of him biting someone who has authorization to be on your property. Sucks because even if someone breaks into your home, and is bit by your dog, the dog will have to be registered as a "biter", and if it happens again, the dog will be put down. You know your situation better than I, but I dont take any chances with my dog at all. Its for his protection as well. BTW, My friends Doberman is a registered "biter" because he got after a guy who was steeling his lawnmower and the guy got hurt running from the dog...didnt even get bit. Now a good dog has one more chance to stay alive. Terrible.