While I'm no fan of formalized net neutrality rules (I worry a lot about rent seeking opportunities in any large dscale regulatory environment) - the way networks are blocking Google TV is over the top - and since it's aroused precious little protest, is likely to lead to a very "walled garden" sort of future, where you'll need a bunch of devices in order to get access to all of the content you want:
Now as it turns out, browser client info is not the primary blocking mechanism being employed by Hulu, NBC, and other sites engaging in GTV blocking. On all affected sites I've tested so far, the serious blocking occurs during the process of Flash video playback startup, where an "unsupported device error" will appear.
Google customizes the Flash Player ID, which can't be (easily) mucked with by the end user. This has its stupid aspects as well; all Google really needs to do is stop customizing that ID, and the problem will vaporize (at least until the networks come up with some other lame blocking scheme).
That's the thing we'll see more of, I think - stupid cat and mouse games where content is there, and then isn't. That serves the interests of the big providers, of course - they would rather keep you glued to the time slot driven, well understood ad model world of broadcast TV.