This legal clause doesn't absolve BikeTown's operator of liability -- at worst, it lessons it and shifts a proportional amount on the user. And cyclists can opt out with an email or by not using BikeTown at all. No one has to take risks they don't accept. 

This clause has been characterised as an underhanded corporate gambit. But I believe BikeTown's operator, Motivate, is actually a progressive enterprise trying to create greener cities. It'll do this by establishing a stable business model for a financially tough industry. 

Another point is that BikeTown doesn't cost local taxpayers anything. That's unique. In the US, systems normally take a 20-70 percent operating subsidy -- and it's higher in Europe. If Portland isn't happy with this liability arrangement, it'll have to ante up to cover the operator's insurance burden.

Bottom line is that bike-sharing stands to make Portland's streets safer and users trimmer. Helmets or not, it'll be a net benefit for Portlanders' health.