In this case, it's actually the opposite of blocking, as AA is making its Award Seats available to partners, but not its own members, which is rather bizarre.
Unless AA is trying to get other FF's to move to AA, by "showing" the product by way of award availability. Many timeshares will only allow people to trade in a small # of weeks - or even 1 year in 4. That's to keep new blood coming in so they can try and sell them.
Just a thought...
Eileen