I'm not sure that will work — it certainly doesn't seem to be solving the problem that thaumaturgy brought up. Although it spells out a concrete limit, it does not give any kind of assurance that it's (probably) enough. Lots of companies use that kind of language to make a plan sound reasonable when it isn't. For example, I don't tether or anything and don't watch a lot of video, but I'm still way above the tiny data plan that AT&T says is enough for 95% of its customers. Like, are we counting customers who don't even have smartphones?

I'd rather just "unlimited (note: OK, you can't actually download the whole Internet)" or something like that if you want to get really picky. It conveys the right message while still providing needed information to slower readers.