[i]t is unclear whether or not this is a violation, but it's certainly a bold move if MetroPCS is basing their decision on reasonable network management. This is especially so in light of the FCC's focus on technology in determining what is and isn't reasonable. The evolution to 4G, as the FCC notes (PDF, paragraph 95), "puts greater pressure on the concept of 'reasonable network management' for mobile providers..."It turns out that the issue doesn't even go that far. The only MetroPCS phone capable of working on these 4G plans is the Samsung Craft which isn't really even a smartphone. It would be more accurately referred to as a feature phone. Semantics? Not really. There is a difference. According to the FCC's net neutrality order (paragraph 49), "[m]obile broadband Internet access includes services that use smartphones as the primary endpoints for connection to the Internet." And the FCC recognizes the difference between smartphones and feature phones, as FCC Commissioner McDowell's dissenting statement acknowledges.
Feature phones have limited operating systems that support a more limited functionality than smartphones. The Samsung Craft supports a YouTube widget (their terminology) and access to some social networking sites like Facebook. And while I admit it is not all that clear, the manual seems to suggest that the MetroWEB browser is a rather limited functionality browser. Some video is available via a MetroSTUDIO widget, but it's not capable of supporting Netflix, Skype, or a whole host of other services (although, again, I admit that this is not clear).
So it would be incorrect to say that MetroPCS is blocking access to certain websites or services; more realistically, the plans in question are coupled to a feature phone (not a smart phone) that is not capable of supporting these services. It may be as simple as "there's no app for that" or it may be that the phone's limited operating system does not support some functionality that these applications require. Either way, it's not a matter of blocking, but rather, not supporting. This is an important distinction, because MetroPCS would not be explicitly blocking certain content; only providing a phone that has limited functionality. You may argue that the result is the same, but would a net neutrality proponent argue that all phones must have a certain level of functionality? I would think not.