My DC is diagnosed with ND now but was not fully dry in the day until year 2. They had multiple accidents daily. I sent bags of clean clothes with them. No one understood as they were bright, seemingly NT and I spent a fortune on private assessments to see if there was anything physically wrong.
No one wanted to know about ND at that age despite me raising the alarm bells from an early age (symptoms other than toileting). I again, at great expense, had to pay privately for a diagnosis.
Many people are not in the privileged position that I am to pay for these things privately. So no, I don't think children should be banned from education due to toileting issues. There will be very few parents that actively want their child to not be toilet trained and it's very likely to be a physical or ND condition that they cannot get an appointment to assess and even if they do they'll be waiting 3 years for a diagnosis.