Unless she's gone through an actual appearance change beyond maybe a haircut, Makoto will recognize her (or at least be given pause) the moment she gets close enough to make out the details... and which point Makoto is going to quickly become very passive and controllable so long as Serenity does the talking. She might have a moment of disbelief, accuse it of being a trick or a coincidence etc, but it will certainly stop her in her tracks. And I'm sure at that point Serenity can talk sense into her through references or commentary etc.