or just making sure the seatbelt is clicked, regardless of whether it's performing a functional role securing the carseat.
Interesting... In all my time complaining to Tesla about Leg Crushing Mode, they never mentioned that the seatbelt could act as a signal that there is someone back there. Of course my X just went to the shop for the umpteenth time for FWD issues, so I can't test the theory out yet.
To answer my original post that started this discussion, we have been using 2 Diono Radian RXTs in the 2nd row for many months now, and they have been working out great, with the third seat currently being a Graco infant carseat holder. I imagine soon we will be swapping that out for a third Diono, and the real test will begin.
Hoping the third row becomes a viable option for our older toddlers soon, as our adult family/friends dread having to ride in the third row -- feels pretty claustrophobic riding back there and the spoiler noise is a bit louder than expected.