"Yes, some pupils might have SEN. The document is not directed at them. Yes, some pupils might really have a stomach bug. The document is not directed at them either."
The whole tenor of the document was to assume that any given pupil is lying until they have proved differently.
So in the case of the stomach bug, you first have to prove you have a stomach bug- now how are you going to do that? By throwing up, evidently. In the front of 29 of your classmates. That will be a pleasant experience and I am sure nobody will show any revulsion or ever mention it again...
In the case of SEN, are you aware how many years it tales to get a diagnosis for many types of SEN or SN? Before that, the assumption will be that you are lying. And even after, in the case of pain or other invisible symptoms, how are you going to prove that you are in pain on any individual occasion?
The latter was the situation of my dd. It took several years to get a diagnosis and though the consultant was kind then enough to come into school to explain her condition (which causes severe chronic pain, amongst other things), the one question asked by the staff at this meeting was "how will we know she is in pain?" The consultant looked completely bemused and replied "she will tell you" (dd was 10 at the time so hardly a baby). But their assumption, you see, was that unless you could prove that you were in pain at that specific time, you were lying. They repeatedly told dd that they did not believe she was in pain.
Eventually this attitude of suspicion and the fear of not being believed got to dd to the point where she was terrified of going to school in case she had a flare-up in class. Her secondary were kind and supportive, but she was still obsessed by the idea that people would think she was lying. One day I was at the dentist for emergency treatment when her taxi came. She couldn't handle the fear and took an overdose.
From his pov, dd's first HT did have a point: there was an attendance problem in the school. Maybe quite a few pupils were lying. But the a priori attitude that they all were nearly killed one child who certainly wasn't.
But I am sure they would have said "oh, but it's not aimed at SEN children". It was just that in any one actual case, they assumed that the SEN wasn't really there or wasn't really serious enough to need any accommodation.