The government’s new net neutrality rules went into effect on Friday, and they’re already making a difference.

Sprint (S) had been combatting overloaded networks by slowing down data speeds for its the heaviest users of its wireless Internet service. The nation’s third-largest wireless carrier halted that practice on Friday due to the implementation of the new net neutrality requirements, which cover wireless networks for the first time. The regulations are part of the Federal Communications Commission’s rules approved in February that treat broadband Internet service more like a utility. Sprint told The Wall Street Journal that it thought its policy would have been permitted under the new rules, but dropped it out of precaution.

The company made that decision just before the FCC announced on Wednesday that it would fine AT&T Mobility $100 million for a related practice. The agency said the company mislead millions of its unlimited data customers by slowing down the services once users had reached a certain data threshold. AT&T (T) made the changes to customers’ services without adequately informing them. A company spokesman told The New York Times that it plans to “vigorously dispute” the regulatory agency’s accusations.