If you know are you not an accessory to the "crime"?
How about a brutal analogy for the craic, you come across someone breaking into a car, he's trying to hotwire the car but doesnt know the wires to cross, you helpfully explain what to do and walk on by. Ok its his crime but didnt you help it happen?
I'd accept that you have the lesser responsibility but, all in all, I think people should stay away from married persons..... (sound like a dinosaur I suppose but there you go....)
You don't sound like a dinosaur. It's a fair attitude. If given a choice between a single woman and a married woman, I would always choose the single one because there is a chance for it to go somewhere..
However if I am out and a few drinks have been had and a woman is flirting with me, I tend to ignore anything that might be on the finger! I am not saying I am proud of it but I don't beat myself up over it either. I should point out this has only happened a couple of times in a long and mainly unsuccessful dating life!