I take it you are aware of the thefts of BMWs by OBD key cloning, as shown on Watchdog? And the subsequent free fix offered to BMW owners??
The fix is a joke really, but it involves a FOC vehicle update by BMW.
BMW 'fix' here
http://www.e90post.com/forums/showthread.php?t=766613
Watchdog info here
www.e90post.com/forums/showthread.php?t=742511
more stuff
http://www.e90post.com/forums/showthread.php?t=766167
happy reading.....