Discussion: helmets

wear them on the road, but not on the canal?

Maybe they are using them for something other than cycling. Office meetings?

Strapping a weight on my head makes me less good at looking around, paying attention to other road user and more likely to fall head first. Basically, a helmet makes it more likely I'll fall/be knocked off and less likely I'll be hurt when I do.
So, in busy places where I'm worried about others doing something stupid, I don't wear a helmet. On longer "training" rides where I'm the one likely to do something stupid, I do.
Either way, there's no evidence that helmet use reduces the chance of injury, so it probably doesn't matter much.

Maybe you need a helmet for one-to-one combat on the viaduct?

I always wear a helmet as I want my kids to, and they are much more likely to do something stupid than I am. Also when on the canal I worry about slipping off and bashing my head on the way in to the water. Non-helmet wearers probably have their catastrophising thoughts more under control than I do.

Anyway, it's taking it and not wearing it that confuses me. It must be really irritating having it flapping around your handlebars.

Wearing a helmet probably comes in useful when one of your city's more notorious gangsters takes exception to your riding a bike in the same bit of road as he wants to drive his car and decides to resolve the matter with his fists, as happened to someone just down the road from my office the other day.