I would be very worried. 1. If they aren't dog people they probably don't know about toxic food for dogs. 2. I would also be worried that this friend might have a motive for feeding the dogs. As we all know, these are very expensive, very popular dogs. Drugging and dog napping them would be very easy knowing that they will eat anything that is thrown over the fence. Call me paranoid, but I always worried about our bullmastiffs because of the idiots who fight dogs. I worry about someone wanting to make an easy profit from these guys.