Exactly. Unless the channel is so active that text is scrolling constantly, people generally notice what people say to them if they are there. If they aren't there, any amount of highlighting isn't going to help.
If the person you are talking to is not paying attention to what you're saying, then complain to the person. It's like talking to someone and they're turning on the TV and watching it without paying attention to what you're saying.
Personally, I think nick highlighters with tab completion work just fine for the situations where you want it to stand out.
