Probably a naive question, but I thought experienced dog people might have some idea if he would sense danger and be protective in spite of his lovely nature! Our dog is REALLY friendly and will go to anybody. I wondered if he would make a fuss if someone actually broke in and started taking things. I think he would bark - but his tail might well be wagging.
Also, I've wondered what he would do if one of us were actually attacked while walking him. Sorry to be thinking grim thoughts, but I had a panic at the weekend where dd went missing for a bit with the dog, and many things flashed through my mind.