Electric Power Assist

Not to be a fearmonger, but the time will come when we start running into people on the trails sporting electric power on their mountain bikes.  Clearly a motor changes things and maybe won't be a policy challenge.  But, I am curious what others think...

Example:

http://green.autoblog.com/2010/05/26/m55-bike-evo-001-electric-escapes-v...