>If you have someone filtered, and they post the first message, it appears that you still see the message, even if the header doesn't show up in the top window.

I'm not sure what you mean.

The filter doesn't keep you from messages if you really want to see them. It only keeps them off the new messages display. If you use Next from a message, Map or See entire thread, they will be displayed. They are also available from the Calendar.