Heard it a few times and it certainly seems like something that would happen but is there any proof or real world examples?
Can an Appraiser just make something worth $20m based purely on their say so?
EDIT: Thanks some great replies! and yeah i was asking more about the tax evasion part than the 'modern art is bad lol' angle.
I guess it depends on the art. I think the market has lifted some frankly crappy art to be worth millions for bulshit reasons that being said the reverse is also likely true and there might be another Picasso out there who can't sell a painting