1) It doesn't deal with bannered routes in the context of usai <-> usaib and usaus <-> usausb. So I'll grant those cases, sure. I believe in all other cases bannered routes are in the same system as their respective parents. This, however, I see as running into the definition issue of "What's related?"
2) Not a problem. Incompletely filtering out some-but-not-all of the noise is better than filtering out none at all. Filtering by system may not get us
all the way to where we want to be, but it can get us
most of the way there.
the issue is the unrelated routes dragged in (and the related routes excluded by a filter).
1) is potentially related routes excluded by a filter.
2) is unrelated routes dragged in. We can at least tighten this up, even it by itself it doesn't solve the problem of #1.