Dean Bubley: Disproportionate resources.....

Dean Bubley posts at the Disruptive Wireless blog about "P2P-over-3G from a smartphone." He writes:

Put this app on your shiny new HSDPA Windows-Mobile device (like the numerous upcoming variants of the HTC Hermes, including the "vanilla" non-operator own-brand TyTn) , attach an "unlimited" data plan, sit in a basement with 10 of your friends, and hey presto! An accidental denial-of service attack, and the cell collapses ("breathes") down to the size of a coin, while the backhaul connection gives up too.

So OK, in this eventuality, yes, I'll give in and admit that some form of protection in the network is a necessity. There's a big difference between crass anti-competitive blocking of things you don't like from a commercial standpoint (eg Skype, Google) vs protecting the overall functionality of the infrastructure.