Well, and there's the availability concern -- if it's a critical or time-sensitive message, sending it to the right address with the wrong encryption key is the

Well, and there's the availability concern -- if it's a critical or time-sensitive message, sending it to the right address with the wrong encryption key is the same as the message getting dropped in transit, which is hazardous. Heck, even with a verified key, I've seen it at least once where a critical e-mail came in to a shared key but nobody was around who could decrypt it. When PGP is used only in special circumstances, the e-mail verification almost needs to be refreshed periodically to make sure the owner continues to have control of the account and the key.