Are you taking the piss?

Only a couple of days after the last school story comes the almost unbelievable one of a secondary school in Kent where pupils and banned (note the word - banned) from going to the toilet during lessons unless they have a doctor's note.  Indeed the toilets are locked up except during official break times.  As someone with a rather weak bladder who well remembers the embarrassment of having to put my hand up to "be excused" at school,  I can only imagine the even worse embarrassment of being refused and wetting myself.  Is this just an exercise by the school of power for power's sake?