I personally think its absurd. but then their infrastructure is probably too weak to handle high traffic. at least they want us to think that. its how it comes off to me.
I fell that the internet should be an unlimited plan at a reasonable set price and then cheaper plans that can incur fees for overages. just my opinion. ATT is generally not reasonable in price to me. but you may say well they are on par with everyone else, and yes sure they are but that doesn't mean everyone else is unreasonable too.
So, we'll see. Maybe we are making too much of this and these 'charges' are designed for these exact people. Otherwise if we're talking about people like myself who do lots of downloading or gaming for around 4 or 5 hrs a day, then not only will their plan be fought by regular people like us but also companies like VALVe, EA, Sony and Microsoft.
I don't think they'd want that battle.