I agree it's not just the duration of the conversation, but in my mind that is one component of the whole picture. It's all about the verbal and non-verbal cues. If you are getting intersted or flirtatious vibes, then at the minimum they shouldn't be returned if there is no interest, but that also might suggest it's time to take a break from the conversation and mingle for a while.
Yup. If I'm happily engaged in a fun conversation with a new friend (especially if they seem well-intentioned but not entirely socially savvy) and I feel there's a question in their mind about the type of connection, I feel it's my responsibility to make sure to change the type of eye contact/shift body language/make a casual positive mention of DH/bring someone else into the conversation/etc. to clarify for them without needing to end our discussion. If they seem incapable of understanding the subtle cues, then I should be more directly proactive in redirecting.
Of course, a creep is a creep, but I'm not likely to catch myself sending signals that could easily be misinterpreted - such as an animated one-on-one discussion - to someone who I don't want to be around.
This has articulated everything I've wanted to say about this thread, but couldn't. Obviously, Ted was a creep and completely out of line for thinking a woman talking to him inherently implies sexual or romantic interest. And it's clear that Amy was not flirting with him.
However, I think it is wise to be aware of the signals others are sending you. So no, a long conversation with the opposite sex doesn't immediately signal interest. But it is one important component of signalling interest. So when one is in that situation, as Amy was, if you pick up on other components of flirtation or interest, I think it is a good idea to casually drop either one's boyfriend or lack of interest into the conversation, or to find someone else to chat with.
I think it's a little hyperbolic to suggest shock and outrage that someone of the opposite sex might think a long conversation would signal interest. I know that if a guy who was single
spent an extended amount of time talking to me, I would probably wonder. Not feel that he was leading me on, obviously, but it would cross my mind that maybe he had an interest in me. And if I did not return that interest, I would signal it in some way. That is, in fact, exactly how I started dating
the guy that I am seeing right now. We were at a group event, we spent most of the night talking, and that's how I knew he was interested. Spending long amounts of time talking to one person is a pretty common way when single of testing the waters, so to speak, of attraction.