Actually, there's a hidden assumption here that means that there's
a lot MORE than 3% overlap. Your 14% system blacklist refers to a
blacklist that was tailored thinking "and this list doesn't include
anything from .XY because we country-restrict them already".
Not quite, because country blocking is per user. But I'll take the
rest of my response off list, since it's really a discussion of our
system (which makes it more of an ad than anything relevant to this).
If anyone else wants it, let me know.