Last month, T-Mobile introduced Binge On, its new Un-carrier move that offers free video streaming from 24 services. One service that’s missing from that group is YouTube, and today we may have some more information about why it’s not included.

YouTube has expressed unhappiness with T-Mobile’s Binge On service, saying, “Reducing data charges can be good for users, but it doesn’t justify throttling all video services, especially without explicit user consent.” YouTube went on to tell the Wall Street Journal that T-Mo is degrading its traffic and lowering the quality of video that isn’t included with the free Binge On streaming.

In response, T-Mobile tells the WSJ that Binge On is in line with the FCC’s regulations, can be turned off by customers with the flip of a switch, and that any provider and be included in Binge On’s free streaming by meeting its technical requirements. T-Mobile didn’t exactly address YouTube’s issues with Binge On, but it did say that its customers “love having free streaming video that never hits their data bucket” as well as “both the quality of their video experience and the complete control they have.”

Along with the free video streaming from 24 services, Binge On also “optimizes” video streams from other services, resulting in streams of DVD (480p) quality. The thing is that these video optimizations are opt out, meaning that even folks with unlimited video have to manually turn them off. Not everyone knows that that’s the case, and so a lot of folks may get frustrated when they feel that their YouTube streams are low quality even when they have a fast cellular connection. That’s likely the issue that YouTube has with T-Mobile’s Binge On service.

What will be interesting is seeing how the FCC responds to YouTube’s complaints. FCC Chairman Tom Wheeler has described Binge On as “highly innovative and highly competitive” in the past, but the FCC recently requested that T-Mobile meet with it regarding Binge On by January 15. The FCC explained that it wants to discuss concerns that’ve been raised with Binge On, and those concerns include the biggest video service in the world.