Takes the onus of knowing every fingering off the teacher, makes the learning more student-centered, (which adds bonus points in your T-TESS) and doesn't slow class down while you look it up, all while still fixing the problem at least as effectively as direct teaching.
You can also incorporate this in sight reading to ensure students play accidentals correctly. "Clarinets, in measure eighteen, there's a C sharp - show your neighbor your fingering for that note and make sure everyone agrees" while you continue instruction.
If they miss it again, then it may be more than a fingering issue, go down the row and have them all play it quickly. Still doesn't require the director to know a fingering off the top of their head.