My sister is a secondary school teacher ... and use to drive the small school bus on excursions ... She said the students (teenagers) a lot of the time wouldn't put their seatbelts on ... Which she ' even as the driver' felt unsafe about even if it were a 30min trip away

I have a girlfriend who always volunteers as an 'assistant' to help out when her daughter's have gone on long distance school excursions, she has been doing so since the older one was 5 & she is now 11

... If it were me I would volunteer to go along with your son on the excursion

Maybe not when he is older ... & hopefully there will be seatbelts in the bus by then ???