Sometimes you just get a feeling that people are up to no good, that something's not right.
Has this never happened to you?
I have, and I follow my instincts. And even though I follow my intuition, it doesn't make, by default, the other party the "bad guy," if they haven't exhibit such behavior. Truth be told, I can fault the OP's action nor his readiness, but I think it's a stretch to think that a crime was about to be committed upon the OP.