Originally Posted by endflag
This took me a couple of attempts but the third time wound up being the charm. The main issue seemed to be either that it actually takes more than 20 inserts and removals or I just can't count.
With that said, I can confirm that this still works on the 2011 WRX and when you get it right the seatbelt warning light(s) will go off, and stay off, after those initial six chimes. If they stay on you after the chimes then you need to try again.
I first tried this in my 06 WRX about the time of the OP as well as a buddies 2.5i and my 05 Legacy GT and now again after a few extra attempts it worked for me again in my 2011 STi.
Like he said "the lights will turn off if you did it correctly"
Now if someone could just tell me how to do this in an Audi A4 and my GF would do great things for me