So this thread reminded me that I have never been able to make use of one of those metrocast wifi locations. So I reset the password on my account and logged into the metrocast portal page.
Noticed a link for usage and checked it. Turns out we have a 350GB cap on the highspeed ultra tier of service. And my family apparently gets pretty close (they show last three months of usage) using between 250GB and 300GB per month. We watch Hulu daily and Netflix occasionally, only ever on one TV.
So I am fairly sure on busier months I may have popped the cap (kid downloading games for PS4 or on Steam at 50GB a piece), but I don't remember getting billed for overages.
So I checked Metrocast's acceptable use policy (not updated since 2011, WTF) at
https://www.metrocast.com/policies/high-speed-internet-acceptable-use-policy/ which states that it is our responsibility to monitor our own usage, and going over the cap is a violation of the AUP which they can use to terminate your service if they see fit.
So, Metrocast has my physical address, my phone number, and my e-mail address and has never once, ever, sent me a notification letting me know I may be near the CAP for my plan, but they consider going over the CAP a means for terminating my account. In fact the AUP goes so far as to insinuate that you must be a pirate or running illegal servers out of your home to even approach their cap, which is patently false as our family does it with only a couple hours a day of internet TV viewing and regular internet browsing.