Ha ha ha! This is a beautiful demonstration of how things have changed since my school days.
In the 70s we were coached from a small launch. Once, when a boy cramped badly about 3 miles from the boathouse during a seat-racing session, he hopped into the coaching launch and the coach sculled his boat home. The boy had never steered a powered boat before and this was on a busy section of the Tideway. He lived, but I'm not sure how. Wot larks!
None of my children rows, but if they did I'd be quite happy for them to ride helmetless to a session. One of them trains helmetless on a bicycle, often with me taging behind in a helmet...
Although a wordy bastard myself, I am slightly troubled by the lumpy syntax and wobbly grammar of the letter's author. The scenario has a slight aroma of public school about it, but the written English of the letter suggests shop assistant on an ego trip.
Apart from the helmet malarkey, there is some sense in the letter. A little advice about visibility and maintenance cannot be a bad thing.
I'm sure a simple letter mentioning helmets, maintenance, lights, locks, reflective clothing and behaviour on the highway would be appreciated by all parents and would cover the school in terms of its perceived Duty of Care.
The Draconian 'sent home' thing seems ill-advised. We should be encouraging our youngsters to take part in physical activity, not using it's withdrawal as a sanction.