....but some of us want to preserve what few brains we have left!
Seriously, I think a minimal amount of high density padding will go a long way to keeping the pinkish grey stuff inside the skull cavity - where it belongs.
Having a moderate rear end collision result in brain damage is not my idea of a fun day. Particularly when for a couple of bucks and a few minutes of time the situation can be improved 100%.
Think of it like wearing leathers or a helmet while riding a motorcycle.