[popi]

I would think a similar process is available for BMW X3, but you will need to have a well versed technician on this forum to comment. I personally always wear by seat belt, but as many have stated on this thread - there are times when it is just not neccessary...

How to disable seat belt Chime:
1. Turn ignition to the OFF position and buckles the driver's seat belt.
2. Turn the ignition key to the ACC/ON position (engine does not need to be running), and wait for the seat Belt Warning Light to turn off.
3. Within 60 seconds of starting the vehicle, unbuckle and re-buckle the driver's seat belt at least 3 times within 10 seconds, ending with the seat belt buckled.
4. Turn the ignition to the OFF position. A single chime will sound to signify that you have successfully completed the programming.
Note: The reminder can be re-enabled by repeating this procedure. Even with this reminder disabled, the seat belt light will be illuminated while the driver's seat belt is unbuckled.