Helmets for Whitewaters???

Whitewater rafting is sure super duper fun but some of the safety standards are really appalling.
I was surprised that even in developed countries they make you wear a life jacket however helmet isnt considered necessary.
My recent experience was with a bunch of guys in PA who managed to throw themselves from raft onto the rocks in grade 3 rapids.
Rapids whatever the grade is are caused by rocks on river bed.While some idiots call falling head first into river from raft near some rocks 'adventure of life time', I would call it dangerous stupidity and getting really lucky.You hit a rock awkwardly after you fall from raft you die on the spot.With so many deaths during whitewaters due to heads smashing on rocks I say we should make helmets compulsory everywhere for rafting.