That's been my opposition to UBB ever since it was conceived. The lartc.org site puts it well in that controlling (traffic shaping) an Internet connection is analogous to the postal services: you can influence but not control what's mailed to you, and one only controls how much one sends. One can attach a traffic policer to ingress queues so that applications only receive data at some rate, but that's not necessarily related to how much gets shoved down the line at you. So it is with all the potential traffic generators on the Internet. Suppose someone picks your address at pseudorandom and decides to flood ping you, or repeatedly tries to p0wn your computer...didn't ask for the traffic but I get it anyway, and no reasonable means to make the upstream stop.
It would also be interesting if a carrier (e.g. AT&T) ends up charging you for traffic the company itself generated, such as Web site ads or promotional emails. -- English is a difficult enough language to interpret correctly when its rules are followed, let alone when a writer chooses not to follow those rules.