Here is a cheap, easy and fairly secure, way to go.

I found that a D ring to my helmet would fit over the knob on the end of the brake handle. A small luggage lock can be put at the end of the handle and the helmet is secured. I just keep the lock in the tool bag I have on the fork.

We all like to think of ourselves as rugged individualists. But when push comes to shove most of us are sheep who do what we are told. Worst of all, a lot of us become unpaid agents of whoever is controlling the agenda by enforcing the current dogma on the few rugged individualists who actually exist.