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and if not, you can retrofit the rear facing seats! It is about the same price like the factory delivery.
Just call Tesla and give the VIN and they can tell you if the retrofit is possible. For most cars it is possible.
3. Depends in which country. It could be a legal obligation to provide a button for opening the trunk.
maybe with a picture it is easier to see what I mean:
puuh...you will at least need:
1. Some bolts on the side for holding the seats
2. Different rear seats. Or modify the olds one to hold the child seats
3. A button for opening the frunk from inside
Here you can see how mobileye is doing their croud-sourcing algorithm. I would speculate that Tesla is using it the same way or is using directly that technology.
Professor Amnon Shashua CES2016 PressConference - YouTube