Happens all the time.... yesterday we had a new sub on campus and therefore alot of kids began trickling in with a variety of complaints. For example, one complained of a stomachache, but when asked what he'd had for lunch, he replied "four tacos and two chocolate milks". After a temp check, he was sent back and told his food would digest just fine while doing his work

). Luckily, we have a "core" group of subs so they know the "frequent flyers" and "complainers".
I have a "When to Send a Student to the Nurse" outline which I give to the teachers to put in their sub folder. Not really sure if it helps, but it's a good try!
Have a great one