No, as already explained, a child standing due to lack of seats, is DIFFERENT from a child sitting 'safely' & then ordered from seat by teacher to accommodate imaginary septuagenarian war vet, assuming both are catapulted down carriage by sudden braking.
The 'lack of seats' victim is unfortunate, the 'turfed out of seat by teacher in charge' victim can righteously sue the arse off the school & get the teacher disciplined.
It is a bit daft. But the teachers aren't the ones to blame here.
& the ultimate consequence of this sort of bollocks = fewer trips. No teacher has to organise one; we do it because they're educational & fun, if hard work.