Sorry to follow up on myself. I should mention that our product can operate in a mode whereby it holds all mail in the quarantine except from whitelisted senders. We also have a "whitelist-people-I-write-to" mechanism, so I guess we anticipated the OP's "new paradigm" by a few years.
I estimate that fewer than one in 10,000 people uses the quarantine-everything mode. I happen to use it on a honeypot address that only ever gets spam (for Bayes training purposes), but I'm personally unaware of a single customer who actually uses it for a live email address. Regards, David.
