Seattle is located in King County, which has a mandatory helmet law for all riders, regardless of age. Melbourne, Australia has a program with helmet laws and it has struggled to maintain ridership. This is definitely a concern. Vancouver, BC is also launching a program in a similar situation, so people are watching it closely.
There is undoubtedly a solution out there, but it may take some time to see how users adopt helmet requirements. We're definitely excited about the Puget Sound planning that is going on. I would love to see bikeshare in my hometown!
The concern to me is less the helmet laws and more the fact that it's not actually safe to ride bicycles in most American cities without a helmet. It's not like we have physically separated bicycle routes like Copenhagen or anything--it's a basic safety precaution.
I agree and was really surprised to see the rider in the video not wearing a helmet, even though it is legal to do so in California if you are over 18 (it is not, however, smart). The answer is to just carry one with you-- they aren't heavy, and you can usually strap it onto a backpack when not in use.
I've had the pleasure of talking to the guys from ViaCycle. Koji himself is a UW grad. Apparently it's difficult to do bike sharing in Seattle because of King County's helmet law.
