Entirely agreed. On the other hand I have what is turning out to be a
unique (here) point of view about this. I don't want to prevent this
kind of theft -- I want to discover it, and remove perpetrators from any
IXP where they try it. I don't want to block it. I want to ensure that
it is never tried twice. I appear to be in the minority wrt this view.
This sounds like a line of reasoning that would argue against filtering in
routers: "I don't want to prevent [this activity, whatever it might be]
-- I want to discover it..."
What sort of filters do you put in your routers?