Alpha test of MAE filtering capability

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?