One of the biggest selling points of AT&T's DirecTV Now service is that it streams video without counting against data caps on the AT&T mobile network. But T-Mobile USA customers will also be able to watch DirecTV Now without using up data, the carrier announced yesterday. DirecTV Now is one of the latest services added to Binge On, which exempts dozens of video services from data caps as long as customers are willing to limit mobile viewing quality to about 480p.

T-Mobile also promised to reimburse customers for DirecTV Now for 12 months if they port a phone number from the AT&T network to T-Mobile and purchase at least two lines. This offer consists of a $35 monthly bill credit, enough to cover the DirecTV Now promotional price. This is a limited-time offer and cannot be combined with other offers like "Carrier Freedom," which reimburses customers for early termination fees when they switch to T-Mobile.

Customers who want the $35 monthly credit must sign up for the new $70-per-month T-Mobile One plans, which have no data caps but impose limits on video resolution and mobile hotspot speeds unless subscribers pay extra. The Binge On data cap exemption is only necessary on other T-Mobile plans that have monthly data limits.

T-Mobile generally says video providers must cooperate on meeting technical requirements to qualify for Binge On. But it's not clear whether AT&T actually worked with T-Mobile on this—it sure doesn't seem like the companies are cooperating based on a statement from T-Mobile CEO John Legere.

“AT&T wants you to think DirecTV is theirs exclusively, but that’s a load of crap," Legere said in T-Mobile's press release yesterday. "Both DirecTV Now and the DirecTV apps stream free on T-Mobile with a faster, more advanced network that covers nearly every American. AT&T is so distracted by their new businesses and DirecTV that they continue to ignore their 110 million wireless customers. Luckily, the Un-carrier’s here to show them how to actually take care of customers!”

T-Mobile also said it believes AT&T customers will end up preferring T-Mobile "even if you hate DirecTV NOW (we offer no guarantees, since it’s an AT&T product after all)."

As Legere noted, T-Mobile already exempted the DirecTV satellite service's mobile video app from data caps. When T-Mobile announced Binge On in November 2015, it exempted its own video service and rival video services from Verizon and AT&T, a move that may have helped fend off net neutrality challenges. DirecTV Now is a new online-only service that customers subscribe to separately from the DirecTV satellite plan, so it apparently had to be added to Binge On separately.

While T-Mobile does not charge competitors for data cap exemptions, AT&T exempts its own video from data caps while requiring other companies to pay for the same privilege. Federal Communications Commission officials recently accused AT&T of violating net neutrality rules with this practice, but AT&T yesterday told the FCC that the accusation is "nonsensical." AT&T probably has little to worry about because the FCC under President-elect Donald Trump will likely be run by opponents of net neutrality rules.