Q: When you’re in your local coffeehouse, and a member of the opposite sex sits down, and you start talking about existential philosophy and music, is it appropriate to mention to this person that you’re in a happy, stable, 6+ year relationship?
A: You can never be assured of anybody’s intentions, and it seems somewhat presumptuous to assume that they’re interested in you. I have all of five friends, and I might be overreacting a bit here. Can’t people just be friendly? You tell me.

as long as presley knows, i don’t think you need to say anything about it to the coffeeshop person unless it comes up.
I’d probably slide the significant other into conversation in a subtle way, just to make it clear without showing that I presume this stranger has an interest beyond friendship, but that’s just me.
I also agree with Sara though, that as long as the SO knows it doesn’t matter too much.
ok. waiting for the S.O. to chip in here. Today, I’m going to go to a different coffee shop.
i think i was going to say that yesterday, but i forgot.
Did she initiate the conversation?
Oh yes, Tbone. I rarely say more than “black columbian for here” in there.
And she said “white intellectual to go”?