I have ocean front property in Arizona to sell anyone who would sign a piece of paper from a dealer about what oil they are going to use.
Some people are a couple of cans short of a 6 pack. The reason anyone would sign something like that are ignorance, high pressure poor sales tactics, and fear.
Just like I'm sure that Polaris sells a lot of oil by printing in their manual that Polaris Blue is the correct oil and that the warranty is void if that's not used. Lame