What matters is:
(a) whether you clearly communicate which kind of video it is, or make misleading claims
(b) whether you clearly communicate dependencies, release schedules, etc.
(c) how things are framed, e.g. whether the video is shot on a test track or things are made to appear like they are in an everyday situation
If you look at other similar promo videos from other OEMs at that stage of development, you'll find that they often take place on e.g. locked-off test tracks where each car in play is driven by a professional and often pre-faced or end with clear words on product availability and what it's subject to.
Some of these OEMs are even willing to take the liability for their product once it becomes available. These come from the same place ...
(Disclaimer: I work for a competitor.)
> Weight-loss products accounted for 13 percent of the fraud claims submitted to the F.T.C. in 2011, the most recent data available. That is more than twice the number in any other category.
https://www.nytimes.com/2014/01/08/business/us-charges-4-com...
It is not legal to do so when it materially misrepresents your product.
The key detail here is that the engineers went off and 3d mapped a route and used that to operate the car. That's not actually something the product does. That's fraud. You can totally produce that video and say "Here's how autopilot will work in the future" because you're demonstrating the intended behaviour, not claiming something about the current product. What you can't do, is fake what the product can do today, and then claim it's capable of that today. Unless Elon Musk plans to personally go and 3d map every journey I take for eternity then that's not an honest claim about how the product behaves.
Note, we're 7 years down the line, and autopilot still doesn't work. The average age of a car is about 12 years. So if you saw that advert, bought a Tesla, you bought it under the understanding that it had a feature it still doesn't have and your Tesla is (edit:~~half~~) quarter-way to being scrapped.