Chris Foresman over at Ars Technica spoke with Sling Media regarding AT&T's recent announcement that they'd now allow SlingPlayer to work over 3G, and general manager John Gilmore had this to say:
"We actually have been working very intensively with AT&T to get the 3G streaming approved," Gilmore told Ars. "Over the course of the last couple of months, they have been testing the app in their labs."
Gilmore said that AT&T was able to determine that SlingPlayer Mobile wouldn't significantly impact network performance after extensive testing. "We always felt comfortable that that wasn't the case," he told Ars. "As we built our relationship with AT&T, we were able to prove to them that our app wouldn't cause a negative customer impact. We always felt that our app was a 'good network citizen.'"
Gilmore further said Sling didn't change any code for AT&T but that they have, and will continue to improve it.