Had a big off last time I was at swinley and really belted my head off the hardpack.
Did not knock my self out but had a constant headache for four days after.
My helmet was badly scuffed, cut and large swelling above left eye and the left lens of my safety glasses was scratched to bits.
I always wear a helmet but don’t normally wear my glasses at swinley, normally just for local natural trails where overgrown bushes or branches can catch you face which Is not a problem at swinley.
I am sure I would have lived without protection but would have hurt a darn sight more and would have not been pretty.
That said if an adult decides not to wear one for what ever reason that’s their look out.
But I do find people who ride with the children not wearing helmets a little irresponsible despite the things my friends and I got up to on our BMXs 30 odd years and never suffered more than cuts or bruises .