I'd like to believe that CAN's would make the last mile problem a memory, but just as soon as people get access to a valuable resource, at super low cost, the abuse will happen. Just look back a few years to AOL's move to a fixed price model for unlimited access. That led to a massive increase in average online times, and severely taxed the modem pools. It was bad enough to warrant a class acton suit.
What do you think the CAN owner/operator will think when they see the bandwidth consumption rates when Limewire freaks find a megabit in the air?