Us east coast rafters wear our helmets, id rather run a tech class 4 without a pfd than a helmet. I mean most rivers out east are shallow and rocky, your not gonna flush drown but you will hit your head and die in a foot of water.
Out here, I leave it off most of the time.
Kayakers need the highest level of safety in a helmet. Lots of good helmets out there for y'all. I recommend, grateful heads. They are hard to find and even harder to have made new (dudeman is too busy building boats outa carbon and glass to bother with helmets)..but they are the best, period.