Verizon's measures have drawn few complaints, and indeed, may have gone unnoticed even by the "5 percent."
T-Mobile USA is up front about the level it starts throttling at: 5 gigabytes. AT&T subscribers have no idea if they might be among the top 5 percent until they get the warning, which is soon followed by throttled service. While Trang was throttled at 2.3 gigabytes, he knows other iPhone owners who are using 5 or 6 gigabytes per month with impunity.
"It seems very random," Trang said.
Sprint Nextel Corp. is hanging on to unlimited data plans without throttling, alone among the "Big Four" national wireless carriers.
Tallman sees few prospects for a lawsuit against AT&T. The company is still providing unlimited data usage to throttled customers, even if the speeds are so low as to make the phone useless for anything but phone calls and text messages. The company made no promises that "unlimited" data would always be coupled with high speeds, he notes.
"They just guaranteed the highway. They didn't guarantee the speed limit," he said.
AT&T's July 29 letter on throttling: http://bit.ly/qddCeI
Verizon page on its version of throttling: http://bit.ly/pMMCfs
Peter Svensson can be reached at http://www.twitter.com/petersvensson
Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.