That is false.
On LTE devices it starts at 5GB.
On 3G devices is at 3GB.
Educate yourself first before you act like you know or what you think they actually start throttling down at.
I been with an unlimited data plan since the 1st iphone and with every iphone since then. How would you know its BS? Are You even on AT&T unlimited data plan or just talking without a clue?
http://www.att.com/esupport/datausage.jsp?source=IZDUel1160000000U
Correct for 5GB on LTE. I was throttled last month on my 5s once I reached 5GB. I was still able to stream music and have my biking app track my ride via GPS with not problem. I even tried a little Netflix. It definitely took longer to load but once it buffered it seemed to stream ok. I only watched for a few minutes so it's possible the video would start to stutter at the throttled speed. But everything else worked fine. For my use, it just confirmed I want to keep my unlimited data plan.