[yodsanklai]

> It's just a matter of how bad it can be without it.

No, it's a matter of how bad it can be without it, but also, how likely you are to fall on your head. For instance, concussions are still common in car accidents despite the safety belt. Do you wear a helmet in your car? following your reasoning, you should.

> I really hope, for the safety of your potential students, that you don't teach anymore.

Everyone is free to decide what level of risk they're willing to take. This is true of wearing a helmet while skiing, but many activities are potentially dangerous (driving, cycling, sunbathing...) and we don't accuse people doing these activities of being foolish.

I'm not advising anyone not to wear a helmet, but as long as I don't have the obligation to do so, I won't, because I feel it's more enjoyable to not wear them.