Yes, it's true when I'm interested in a girl I look if she's wearing some ring indicating a relationship. Some girls really do wear a ring for the sole purpose of fending off attention. One very flirty girl at work wears such a ring. She's not married and even told me it's just to ward off attention but she's too sweet and flirty with guys for it to day any good.
I tend to think when I see a ring is that she's in a relationship. The ring has to look valid. Sometimes it's clear the ring is just some worthless thing she put on her finger.
A lot of the time, it's the VERY first thing I look for after I decide that she's attractive. If there's a ring there, it doesn't matter if it's a 400 carat rock or a twist tie, I immediately extinguish any thought of making a move. If it's a serious ring, obviously she's off limits. If it's a ring that she "just wears" on her ring finger, then I think that's extremely inane and I doubt I would be very attracted to a girl like that.
easy answer if I see a wedding ring, I back off. No flirting. If I think she is nice and pretty. I'll talk but try to catch myself from flirting. Oddly, sometimes these tactics backfire and they start sending the signals of being interested. I got a problem there.I Probably should ask a question about it.