These bikes that end up in the water are presumably not being thrown in by bike riders, but by vandals and pranksters. Is it possible that some of the poorly-parked bikes are also the work of individuals just looking to cause trouble?
Though I like the UW's efforts to improve the situation by creating designated bike-share parking, and having the companies enforce it via GPS, I suspect the long term solution to badly parked bicycles will be for these companies to abandon docklessness.
