The chin strap on the old steel pots did not go on your chin, it went under your jaw. If you fastened it, it chafed. A lot.
The steel pot was designed to protect you from shrapnel. It evolved from the (literal) tin pots the Brits wore as overhead cover in WWI, dropping down to offer some ptotection to the side of the head.
The Kpots do offer ballistic resistence, so I'm told. As such, one would want it to remain firmly in place so that it could provide that protection, as opposed to the deflection of spent shards of metal the old steel pots were good for.
As required by law and custom: In my day .......
you could wash your feet in your helmet
you could dig a foxhole with your helmet
you could cook a meal in your helmet
you could take a dump in your helmet
while these young whippersnappers can't even ...................
stay safe.
skidmark