As noted by DSL Reports:
Sprint does have terms and conditions which prohibit certain types of data use that may impair other customers’ usage or harm or interfere with the network. At yesterday’s investor conference, Sprint CEO Dan Hesse was referring to Sprint’s right to terminate service of data abusers who violate Sprint’s terms and conditions. Customers who abuse our network by violating the terms and conditions will be contacted by Sprint in an effort to have the customer change their usage to comply with their subscriber agreement. Customers who do not change their usage and remain in violation of the terms and conditions may be subject to actions reserved by Sprint, including but not limited to termination. Consistent with our advertising, engaging in such uses will not result in throttling for customers on unlimited data-included plans for phones.
This was how in the late 90s, early 2000s, ISPs dealt with their ‘heavy users’ (aka ‘early adopters). You’d typically get a semi-threatening phone call, with the person on the other end refusing to actually say “we have a cap of X amount of data per month” while simultaneously suggesting that your usage was at an (unspoken) amount that “was unfair to other customers.”
Only once, in many phone calls, did the person on the other end come clean. My account had escalated to a VP of the company and, surprisingly, the VP called me rather than give the case to a flunky. I think he was just curious to talk to someone who used amongst the most bandwidth in the country (I was 9th heaviest user on a ADSL connection for two months straight). He spelled out that no, I wasn’t really being “unfair to other customers” in the sense that I was consuming all the available bandwidth - the usual trope that was trotted out - but that I was being “unfair” in the sense that my level of data usage was so high that the data transit costs associated with my account were incredibly unprofitable for the company. I think they had to line up something like 150 other accounts against mine to be revenue neutral! The call was good though: I got a one hour lesson in the costs of data transit and a request - not demand - that I either reduce my consumption below a certain aggregate amount per 3 months or else I’d have to find a new carrier. I ended up sticking with them; while I wasn’t happy with complying with the request, it was by far fairer than any agreement I’d have gotten with one of the large ISPs.