Stacey: I am not sure if someone on this thread has already said this, but keep in mind the way things work in a room of people.
If a guy is looking at you, yes. It's on him to come over to talk to you. But you have the chance to flash him a smile to *invite* him to come talk to you. Women always have ways of telling a man whether or not the pursuit would be welcome before he starts pursuing.
So, in short, you can view sending emotigrams as the equivalent of the smile, and he should respond hopefully with a fuller message. Personally, I dislike receiving a blank emotigram, so it wouldn't hurt to type a sentence or two with the emotigram. Blank emotigrams either say "I have no confidence!" or "I am not subscribed!" and neither are good signals to send. I can't say all guys would think that, though.
So, I would encourage you to do this and not consider it a role reversal or off-putting. It *is* slightly more active than flashing a smile, but that is because online we have to type more to compensate for not having online body language.
Peace and grace!