Verizon throttled their unlimited 3g plans for years (apparently they just stopped this month: https://www.washingtonpost.com/news/the-switch/wp/2015/08/13...). They planned to do this to 4g unlimited customers too, but backed off after a stern warning from the FCC. I have friends who are grandfathered in their unlimited plans and as I understand it they do everything they can to get you off of it.