I bet you cut the tags off your mattress tooI don’t know, I’ve had a boatload of new cars over the years. Tons of warranty work at various times for various engine related issues. Ford, Hando , Nissan, GM, etc, have NEVER asked for proof of what type of oil was used. Just as long as there was oil. Either this is the OPs first car, or some service department messes with him, or he flat made this crap up.