I'd disagree with that. With the "Unlimited" plan, there's a definite mandate for the provider to shape and control the usage of traffic to ensure that its divided equitably. In theory the traffic management should be done without regard to the content, merely to curtail the bandwidth being used. Essentially you have a bottomless cup of bandwidth, but you're giving AT&T leverage over shaping the pipe.
When you're metering traffic, the cap is what is should be doing the shaping. The user is paying for an allotment of bandwidth, its up to them to use the resources as they see fit. Now I've got a fixed sized cup, which means AT&T has much less of an interest in shaping the pipe.