Jack already sort of explained what I meant, but here's an example
Assume that youtube's prefix had a roa like this Origin ASN: AS36561 Prefixes: 208.65.152.0/22
Now AS17557 start to announce a more specific: 208.65.153.0/24. Validators would classify this as Invalid (2). If we would only use local-prefs, routers would still choose to send it to AS17557 (Pakistan Telecom) as it's a more specific.
So in cases where the invalid announcement is a more specific, the only way to prevent 'hijacks' is to actually drop these 'invalid' announcement from day one.
yes. and your point is? we all run our routers according to our views of what policy we want. some folk will want to drop that, i encourage them to, and have done my best to see that they have the capability to do so. i am in that camp. others fear rir and black helicopter control of their routing. they may not want to drop the 'bad' announcement. i tried to document how they might do so. we all have choices. the point of the design is to empower the operator to make those choices, and to do so in a simple and consistent fashion. randy