You know what people really don’t like? Data caps. They don’t like them on their mobile phones and they really, really don’t like them on their home Internet services. This hasn’t stopped Comcast and other wireline ISPs from trying to ram them down consumers’ throats anyway, although customer resistance to such caps is so strong that the companies wouldn’t dare roll them out nationwide just yet.

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We were reminded of just how much people hate data caps when reading some recent complaints flagged by The National Journal from fed-up Internet customers who are sick of worrying that they’ll get charged extra if they watch too many shows on Netflix.

“I have to tell my kids to stop using YouTube and other services and stuff they need for school so we don’t go over the cap,” one customer wrote to the Federal Communications Commission.

“Please, please make data caps illegal!!” fumed another.

Data caps are not illegal, of course, but they do raise net neutrality-related concerns. If Comcast were to try enacting a program like the “sponsored data” program AT&T has been trying out, it would have the potential to seriously distort the balance of online commerce.

For those who don’t remember, the “sponsored data” program lets companies pay AT&T in exchange for having their apps’ data not count against bandwidth caps. So for example, if Netflix wanted to give customers the ability to stream shows on an unlimited basis on their phones without having to worry about overage charges, it could pay AT&T to not have them count against the cap.

To be clear, AT&T’s program hasn’t been a rousing success so far, mostly because customers who are worried about exceeding data caps on their mobile services will instead stream shows online using their home broadband connections. But if their home broadband provider took away that crutch and started imposing strict data caps, then users would have nowhere to hide to escape from potential overage fees.

And don’t be fooled, this is exactly what the cable industry wants. Michael Powell, the former FCC chairman who is now the CEO of the National Cable and Telecommunications Association, said in 2013 that cable companies needed to move with “urgency and purpose” to implement a usage-based pricing system that gets rid of unlimited data in favor of data caps.

So it’s not at all surprising to hear that the people who have been subjected to data caps in test markets absolutely hate them. The cable industry knows everyone hates them but because the home broadband market is so uncompetitive, it also knows that consumers in some markets have little choice but to suck it up and deal with them.

Whether the FCC decides to aggressively investigate whether bandwidth caps are being implemented in ways that violate net neutrality will be a big story to watch over the next year.