Warning, heavy users: T-Mobile just now turning on data throttling?

T-Mobile had become the only top-tier carrier in the US to endorse data throttling over capping back in April, and at the time, we'd thought the feature was being turned on immediately -- but new communication being passed around internally has us thinking that they're just now getting around to flipping the switch. A screen up on TmoNews says that the policy will start this Saturday, October 16, after which exceeding 5GB of data usage in a month will result in "web browsing capabilities... at slower speeds... which will be determined by [the user's] device type." If it's any consolation, the same screen says that less than one percent of users will actually be affected in practice... and something tells us most of you know who you are. But hey, getting throttled is still better than getting slammed with overage, right?