It would either have to be pooled subscriptions, or a maintained set of different, per-site workarounds (using specific referrers and/or user-agents, disabling

It would either have to be pooled subscriptions, or a maintained set of different, per-site workarounds (using specific referrers and/or user-agents, disabling or modifying on-page javascript, hidden urls, etc) or a mix of the two.