I'm not sure if a stranger would be brave enough to make a grab for someone else's pet. I guess other pet owners might experience that sometimes. But we do have guests who want to hold the pigs when they come over. We have to warn them not to be too pushy about it, though. The pigs don't scratch too deep, but they could bite right through your hand.
The pigs used to like tiny humans... When we had some at home.