Pass side airbag
I think (and this is only personal exp) that pressure on the sides will also de-activate the passenger airbags as well. This CMAS we got one of those heat/vibrate thingy's for the car that plugs into the cig lighter. Interestingly, this is just the one that is for the back (there is no part that you sit on). There was no issue as long as it was sitting there, but it kept falling forward when no one was in the seat, so we finally used the elastic strap that was attached and wrapped it around the seat to hold it vertical. As soon as we did that, the "Pass Side Airbag Off" light comes on whenever there is no one in the seat. As soon as we go somewhere together and there is someone sitting there, the light goes off. Get out, and it comes back on, and there is no pressure on the seat, only the elastic strap that goes around the seat back.
jeff