Blame Video
Nah, blame Comcast :-).
If using "too much" bandwidth is a problem some users are causing, the obvious technical solution is simply to throttle the bandwidth to that user. Comcast servers assign the IP address, Comcast servers know which IP goes to which user. Surely the router technology exists to delay delivery of packets to particular IP addresses, thus reducing the effective bandwidth, but this would all require technical competence -- an attribute hardly ever found in cable companies :-).