Net neutrality has seen headier days, and to be honest, it never stood a chance in the wireless industry — but T-Mobile just drove the point home at its Uncarrier 6.0 announcement in Seattle this evening. With a new initiative its calling Music Freedom, a handful of music services will be blessed by the carrier so that they dont hit subscribers monthly data allowances. It sounds wonderful — and right in line with the uncarrier image that firebrand CEO John Legere has worked so hard to cultivate — but its a terribly slippery slope: T-Mobile has decided, arbitrarily, that some of the data traveling over its pipes should count against a cap, while other data should not. Whats to stop it from using data cap exemptions as a punitive measure against content providers that arent on good terms with T-Mobile (or its parent company Deutsche Telekom)?