If anyone thought that ISPs were going to get away with setting up their own private gardens, they should have gotten a wake up call this morning. Read through this Bostonist post to see what I mean - by the second update, it's clear that the "blockage" of Google services was due to a router problem. In the meantime, the story hit techmeme (and everywhere else) - and I expect that Comcast's helpdesk was inundated with calls.
Bottom line: Attempts to create walled gardens aren't going to succeed, period. If this level of uproar accompanied a transient outage, imagine the PR nightmare that would follow a real downgrade.