I get your point, but it works only if trapperlarr can count on future spurious emails coming from none but the same sources; otherwise, it could conceivably generate a list of rules a mile long.
I don't think a long list is an issue.
Depends on your point of view, I guess.
I can't speak for trapperlarr , but I prefer to get to the root of a problem and not fall back on a workaround unless it's absolutely necessary.
If trapperlar's problem is just a basic spam issue with which hir ISP can't deal, yours is the way to go, but if it's some other sort of problem, best for it to be solved.
