To a sincere person, it may play on their mind and make them ask more questions. To a fully in indoctrinated pious JW, it stops them dead in their tracks and makes a point:
Way back when I though that something like this would matter, the problem was that the JWs that camt talking to me had not good intention nor sincere interest in me or my well being. They only wanted to get "juicy dirt" to talk among themselves.
I'm sure that's not the case with all JWs, but my reality was nothing that would make me try to reason with them. They were nasty people, they were ill intended, the couldn't care less about what they should do as JWs, leave alone caring about me as a person.