You sound very polite! I often expect people to say something mean, but I've never had that happen, and it makes me very happy!I haven't had anyone say anything to me for vaping in public oddly enough, I have had people ask questions about how it works and whatnot.
If it happened I would simply ask them if I could help them, if they had something to say afterwards I would tell them to mind their own business. If they were courteous and asked me to move since it was disturbing them I would put it away.