And what do you do with a BGP customer which sends you traffic from prefixes he doesn't want to announce to you? There are such customers. Fail filter ACL?
This has been my question with uRPF from the beginning. You can solve this on for some networks, but it doesn't scale very well. Especially where you really don't know that your customer's customer is doing this.
It's 2004, and so, your customers who want to do this have to explain why, and you have to maintain extra-ordinary filters for such customers, at either your cost or the customer's cost.
ah-ha! Patriot-Act!
not nearly. i'm not asking you to take your shoes off before you get on an airplane, nor fingerprinting you before you enter the country, nor secretly searching your residence while you're at work. the closest analogue would be wanting your body to be on the plane if your luggage is, and wanting the name on your ticket to be the same as the name on your photo-id. in san francisco before the gold rush, it was absolutely common to see citizens carrying firearms, or to know that they were carrying concealed firearms. by the end of the gold rush this was no longer common because a "carry permit" was required. same city + more people = different laws. you can say that you hate this kind of change, but what you'll really be hating is either the laws of human nature or the laws of thermodynamics. either way, your hate is irrelevant to the final outcome.