In the US there is the wonderfully named Professor Hurt who is the lead for the Bicycle Helmet Safety Institute.
They have major concerns over modern design where ventilation, straight surfaces and acute angles cause what are referred to as "snag points" which can arrest this natural motion and cause rotational forces. These along with teh effect on teh brain of the movement being arrested suddenly may exacerbate injury.
In some cases the helmet has been ejected from the head.
Of course the answer from the manufacturers is to tape the helmet to the head form when testing ... preventing ejection
They are suggesting a return to rounder, smoother safer helmets without these snag points
in the helmet pros i think it is ive posted about this happening albeit with a tree, ive often wondered if a hard basin would of bruhed that one aside. i will use a helmet more or less all the time but they can cause problems just like any other helmet
climbing i cant remember ever cracking my head on anything until i wore a helmet, when in work i dont bang my head until i have to put a bump cap or hard hat on
i spent all my youth riding without helmets suffered a few minor injuries, started riding more seriously bought a lid wear one most of the time
in all my meetings with the floor wearing a helmet ive never snagged it like that video
thinking about i came closest to doing that on my first trip with new hydraulics and the firt time id ever worn spd's
