Also watch out for folk who want to know about your financials or your living arrangements. Those are rarely appropriate for any early-on conversation.
Watch out for inexperienced masters looking for inexperienced subs. I mean, it can work, but why put your trust in someone who knows no more than you do?
And the red flag that I hearken to most, when talking to people at my munch, are those who claim to be leaving their spouse but can't meet you except when they should be golfing... or some other similarly conspicuous time slot.