"Matthew S. Whiting" wrote:

Yes, and this is the reason that PA repealed the motorcycle helmet law
this year. The data just doesn't support it. Having said that, I still
always wear my helmet. The reason being that I believe I don't take
extra chances with it and thus actually am safer. However, across the
entire population, this just doesn't appear to be the case. Counter
intuitive to be sure.

I think the issue of safety features increasing risk is mainly when
they are new or unusual and people factor them into their behaviour.
If they are something you don't even think about I am sure they
increase safety.
An example would be stall warning systems. By this argument, they
should make flying more dangerous because people are more likely to
fly close to the stall. If there were only a few aircraft with stall
warning systems that would probably be true. However because everyone
takes them for granted and wouldn't normally think of them until they
go off, I 'm sure they do enhance safety.
Australia has had compulsory helmet (and seatbelt) laws for a long
time, and I don't think they decrease safety because Australian riders
take them for granted and so are unlikely to modify their behaviour
because they are wearing one.