I work for an ISP, and actually we do have a fantastic way to cap bandwidth; it is called a telephone. We sell a "consumer" service. If you run a warez server or a web server that is knocking down a gig of transfer a day; you should be aware that it is only a click of a button to change you right over to the "business" class DSL. If you want 40GB transfer a month; you got it, but you are going to pay for it. The reality of it is, that as a small ISP, if every DSL customer we had was downloading shit all day long, we would literally need dual DS3's to handle the load. A full DS3 runs around 13 grand a month; so, within the guidelines of what is reasonable, smaller providers would not be able to provide DSL at all and it would cost about 5 times what it does now.
Now, we could put it in the "rules" that you can only use X amount of bandwidth per month, bandwidth monitor every customer and shut them off when they exceed their limit.


We can use the phone when we see that you are getting a little out of hand and ask you to knock it off. We prefer to be what we are; a small Internet Provider, which will make an attempt to communicate with you so that we may have lax rules and not a pissy corporation that shoots first and asks questions later.