Some stranger going the other way... usually say in a slightly loud voice to a riding companion "must and an indestructible head... or no brain to damage"

Someone in a group ride with me ? I tell them they must be a total dick to not use one. In fact I won't ride with them. It may be their head. But it's ME that has to sort the shit out when they've stoved their head in and laying unconcious on the road. Not using one is just being an inconsiderate selfish dick to those who have to sort out the mess. Same with not wearing a seat belt in a car.

Edit. To add. It is pretty shit when you do have to sort some unconcious fheckwhit out.
I've had to do it twice. One of them when half way down an Alpine pass do the the guy's face smashed in. Police, ambulance...etc. nobody I knew. But still nasty with blood everywhere.
Now add in2020, C19 into that mix...