What the others have said. A school or district requiring a KT to be present during class is due to liability reasons, which always apply during regular classes but for some reason some guys in charge think they can be more lax with this during afterschool or camp classes thanks in part to the vague wording in our contracts. As NETs, we're technically here to assist KTs, not lead, so a KT should always be present. But according to our contracts, NETs can lead non-standard classes. This is often interpreted as "teach alone" by a lot of offices, and they feel they have their liability issues covered as long as there is a KT/nurse present in the school somewhere. This bit has always confused me because I don't really get how liability in this case can be rationalized using wording from our contracts as I feel it's a wholly independent legal issue -- maybe someone can explain it to me -- but that's how it is for now. So what you end up with is NETs often teaching camps alone as most schools rotate KTs and nurses to be present at the school at all times anyway. If it falls on the coT to be available, which it often does, they typically just hang out in the teacher's room until it's time to go.
Some schools or offices decide to take it more seriously, though. It could be that a parent complained for whatever reason, or that someone had a little more foresight in case of an emergency (emergencies are often heavily time dependent, and valuable response time could be lost as a result of a NET's lack in training to respond to such emergencies along with their inability to communicate efficiently in Korean, which could and would reflect very poorly on the school and could honestly land someone in deep trouble). It's possible that there was a scare at another school and now certain people want to play it safe. It could be that some old man in charge just wants someone to keep an eye on the NET. It could even be as petty as someone being pissed off at your coT and wanting to inconvenience her. There are so many reasons, and no way to narrow it down without more info.
Either way, if that's what a higher up wants, and you really can't or don't want to involve your coT, especially if it's because she has medical issues, then maybe just make sure she can at least be off of her feet with back support. I'd source a comfortable office chair and a blanket for her.