I do believe that if she was more awake in that scene she would have realized of the 4 people in the academy (she doesn't know Sun told Neptune) that aren't teachers that know whats under the bow, only one of them would ever use a laser pointer to get her attention, and she would have realized it in a matter of seconds, Ruby wouldn't cause that would be rude, Weiss wouldn't because it would go against the whole be a better teammate thing and stuff now that she sees people as people regardless of what they are more so (I am sure there is still some of that left as one doesn't decide to contradict the subliminal messages they have picked up since childhood over night), Sun wouldn't cause he'd end up as a scratching post, Yang however saw it as a non-verbal pun they could laugh about later, or start a food fight over...