Answer for the OP of first page:
Reviewing history, this was used to prepare for the financial market-conditions needed to save Solar City in June, 2016.
SolarCity stock soars 15% on $2.8 billion Tesla bid; TSLA plunges
The big reservation burst and hyped-news of "500,000 cars in 2018 vs. 2020" allowed a very direct go-to-market move to handle saving Solar City from a really bad situation in their finances as installations were waning and the stock was under pressure. The plan worked. Maybe too good. Factory wasn't able to really start building cars until late 2017, long after a promise of 100,000-200,000 in H2 of 2017. The tent recently erected is more of a "we have to make-good at least half-way on claims we made in 2016..."
Thanks for helping Tesla absorb the Solar City shares (primarily Musk's) and running them up again in value. Remember, too, that the big talk about "starting at $35k"... And now, they have to wait to produce it because Elon says it would hurt the company and pressure it further financially. Solar City's internal debt load is still big and Tesla has a "wall" between that entity and itself and has an option, if they decide to, to default on Solar City debts to cure that. We have to wait and see how that plays out as the debt matures.