Have you heard of that trick where you throw the dog a steak? One guy broke into someone's home, and stole a lot of valuables, and stole the Rottweiler too!
I can't speak for anyone else here, but my dog does not accept food/treats from anyone except my wife or I. She'll eat her food from her bowl if the inlaws are babysitting her, but she will not accept any food/toys/treats from strangers unless I am the one to give them to her.