When you are associated to a wireless network and do ifconfig $IF down; ifconfig $IF up, no data is being transmitted anymore. The "RUNNING" flag disappears from the ifconfig output.
However, the card stays associated, indicating that data transfer should be possible.

The behaviour should be:
1) everything should work as before (this was the case for example in the ipw3945 driver)
2) the driver should disassociate from the network

The current state (card stays associated, but no data is being transferred) is inconsistent and unintuitive.

Reference: http://permalink.gmane.org/gmane.linux.kernel.wireless.general/12972