For example, if T-Mobile started charging $10/month to access Spotify on their network, that's an obvious net neutrality problem. What I'm saying is that if T-Mobile lets you access Spotify for free on their network, that is also a net neutrality problem, although many people see it as just a bonus.

Stuff where an entire plan is free is fine. It's when different traffic is treated differently that net neutrality comes in.

A counter example that I bet T-Mobile is waiting to deploy is parental control. As strange as it sounds, there are actually families that pay to have their wireless carrier restrict adult content while on-net.

EDIT: "As strange as it sounds" refers to the fact that most parental control solutions are network-based, when in fact a proper parental control solution should be client-based because as soon as your child goes to WiFi at MacDonalds/Starbucks they probably have access to all the adult content they want to see by bypassing the wireless carrier parental control network controls.

1) they are allowing customers to opt-out (maybe they will concede this could be improved, but it doesn't change their fundamental desire to circumvent net neutrality); 2) content discrimination has positive benefits for consumers (i.e. allows higher consumption of content)

T-Mobile may be willing to bet that the FCC and consumer groups will be hard-pressed to claim that sending HDTV vs. EDTV falls under a discriminatory context given the consumer benefits and (seeming) fulfillment of video service.