Remember kids... always wear a helmet. (The almighty bikeradar helmet thread)

The problem is when non-helmet-wearing gets equated with irresponsible cycling, like by your neighbour.

I ride a sit up and beg, hardly ever bother to filter, and indicate like Brown Owl demonstrating semaphore. Yet because a helmet is such a visible signal of "I care about my safety", and the limitations of that safety so poorly understood, many would judge me as a less safe, less responsible cyclist than the hordes of lemmings that flow past me every day taking far higher risks but wearing a helmet.

So to me, those helmet wearers, the ones who protect against the low risk of a specific low-speed head injury but not the high risk of undertaking a left turning vehicle, are a problem because they confuse the picture of what a responsible, safe cyclist looks like. And that confusion becomes a real problem when questions of accident liability and contributory negligence have to be considered.

...

I'd agree with brokenbetty that when helmets provide a false sense of security and do not cause riders to consider more real and present danger, then those riders are being at best naive, and at worst dangerously reckless.

But she's saying a bit more than that. That by supporting the false view that helmets significantly improve safety, helmet wearing riders shift society's perception of what a safe cyclist is away from reality. Then genuinely safe cyclists get the blame for others faults if they fail to wear the expected symbol of safety.

I think that's a bit backwards. The false trust in helmets springs up naturally from common ignorance, and although helmet wearing cyclists help perpetuate it, they're more effect than cause.