Aha, some more good ideas there! But you're right, there's tradeoffs and dependencies and uncertainties throughout, so it's not easy to even guess in advance wh

Aha, some more good ideas there! But you're right, there's tradeoffs and dependencies and uncertainties throughout, so it's not easy to even guess in advance what would work or be worthwhile. Plus as you say there could be negative consequences from a kind of arms-race, with the solution becoming a problem in itself. It's not the same thing, but I'm reminded now of email in the past, when you would usually get an undeliverable message if something went wrong. But later that was almost entirely stopped - because of spam. Massive volumes of spam was sent from forged addresses, and much of it led to those replies. So that made things worse by doubling the volume, plus the innocents whose addresses had been forged got deluges of confusing undeliverable messages! I think you're right in that changing IPs would be easy for them. But, changing hosts would be significantly more work and hassle. So if the abuse reporting worked, that could have much more of an impact...