Originally Posted by Blumie

This is a different issue than the OP was asking about. At least on AA domestic flights, there typically are two bulkhead seats blocked and unavailable for all passengers, irrespective of one's status. I believe the reason for this is that they are reserved for passengers with disabilities, if needed. But these seats always open up to all eligible passengers prior to departure, perhaps at the 12-hour mark as suggested by this discussion.