"Nielsens Anywhere Anytime Media Measurement initiative (A2/M2) show that the average American watches approximately 153 hours of TV every month at home"
153 * 2GB for every hour is 306 GB of data. So yes, I do believe that some people will find issues with Comcast's cap on internet data.
I estimated 2GB using my most recent downloads from iTunes as reference. Cars was 1.78GB and is 1 hour and 56 min. Monsters Inc was 1.39 and is 1 hour and 32 min.
Wouldn't that be about 1gb an hour?