They probably got the idea from Europe. At least in the UK this is very common practice. Go on a site like Auto Trader UK and search for vehicles with less than 100 miles on the clock. There are thousands of what they call "pre-registered" cars which count towards quotas for things like sales of EVs. The dealer registers the vehicle to itself so technically the buyer is the second owner, although some manufacturers allow the warranty to start when the customer takes it anyway.
That doesn't seem to be the same thing. Say I can buy a brand new car for 30,000. The seller would like to sell more, but if they drop the price to 27,000 then the get 3,000 less per car. Not good. So they sell me an officially "used" car for 27,000. Most people pay 30,000; but there are some who find 30,000 too expensive and live with a "used" car saving 3,000.
The difference is that these cars are actually sold to real customers, who drive these cars for real. They are not parked somewhere in a hidden car park. They are real sales at a slightly lower price, producing overall the highest profit.
What these guys are reportedly doing is losing massive amounts of money to be able to report big sales numbers. If that car cost 23,000 to build then they now have 23,000 worth of car in a hidden carpark, losing money all the time while it ages. Not clever at all.