T-Mobile is taking action to stop users who signed up for an unlimited 4G LTE plan for their smartphones and then use it heavily with tethering. Although T-Mobile says it supports a limited amount of data usage for tethering use, the company says some users have abused the plan by consuming up to 2 TB of data per month.
In online posting, John Legere, CEO of T-Mobile, describes these users as "hackers" intent on stealing data from T-Mobile.
http://newsroom.t-mobile.com/issues-insights-blog/stopping-network-abusers.htm