When DH and I bought our first new Saturn, 20 years ago, all financing was approved before we drove it off the lot. Also, they arranged for temporary insurance from the minute we drove off to the moment we gave our first premium to the insurance company THAT night (we had to drive straight there). Otherwise, they'd repossess the car next day. The salesman explained that in the past, people would drive off promising to get insurance, get into an accident and just let the wreck go back to the car company. Trying to collect from the buyer, who now had nothing, was a nightmare.
I think the process is better streamlined now, but they cover themselves for anything.