Maybe both?

You're right though.....why mistrust a total stranger coming in for a photo shoot? No one would.

On the other hand, even if I suspected they were feeding me a line of s$#t, rather than confront the person I would probably do the shoot to the best of my ability to please the client (another basic trait of a good photographer)

Who cares if it's truth or fantasy? As long as you don't mis-represent what you've done. No harm done after all. Another form of "glamour shots" perhaps.