I recently discovered that I've been unintentionally dispensing incorrect advice about a new Exchange 2007 Edge Transport feature. My shame at getting it wrong is only moderated by knowing I'm in good company. Fellow Exchange MVP Jim McBee recently posted to his blog on this same topic, and so I'll just quote him here:
The feature is just "safe senders"; safe sender list aggregation does not include the user's blocked senders. As Microsoft's Ross Smith pointed out to me, that is why it is called "safe sender list aggregation." :-)
So if you see me talking about how Edge does safe/blocked sender aggregation, ignore the "blocked sender" part, because that's my inner idiot poking out and saying hello.