My T-Mobile plan still throttles YouTube (and some other video streaming sites) to prevent HD video playback unless I buy a HD video day pass or upgrade my unlimited plan to an even more unlimited plan. I don’t mind too much on my phone, since on a small screen 480p is mostly good enough, but I frequently use a VPN on my tablet to bypass the throttle since depending on the content, 480p can look pretty rough on the larger screen.