It simply makes no sense imposing data caps these days. Think about how much more data you use than you did just a few years ago - Streaming services (Netflix, Hulu), digital distribution (Steam, D2D, Amazon), general content, etc.
Time Warner tried this in Austin a couple years ago and it backfired on them. They lost a load of customers. I actually switched to U-verse because of it. They ended scrapping the whole idea. This is their chance to shine and announce: "no data limits" "we miss you come back and enjoy all the Internet" As far as the whole "98% of users won't be impacted by this change" BS... I'm going to call BS on that and go a little further. Even if people don't hit the cap, they like having the unlimited option available. Example: If my hard drive crashes, I have over 300GB of games to download from steam. And that's only the ones I'm currently playing!
Call them and complain (be firm but be nice). I called and got disconnected the first round after a 5 minute hold. The second time when the automated system asked why I was calling I said "I'm pissed off!" I was immediately connected to a rep! The rep said he didn't know anything about it. His supervisor said the same thing.
And if they still go through with this crap - switch. Vote with your wallet folks!