I think the general consensus here is that if people are conversing in public, emote at them and it'll be ok.
The key here however is to emote at them. In my experience, it's not often that when you're by your lonesome emoting to yourself, watching the tavern or what have you, someone will approach you. It does happen on occasion which is great! But don't rely on it, because it usually won't hook anyone. If you show you're actively interested in what other people are doing and have your character in actual proximity to the situation in question, I think you're far more likely to be responded to.
The key here however is to emote at them. In my experience, it's not often that when you're by your lonesome emoting to yourself, watching the tavern or what have you, someone will approach you. It does happen on occasion which is great! But don't rely on it, because it usually won't hook anyone. If you show you're actively interested in what other people are doing and have your character in actual proximity to the situation in question, I think you're far more likely to be responded to.