I'm sure that I am missing something obvious here, but why are car purchases exempt from the threshold reduction? Dealers/dealerships must come under an awful l

I'm sure that I am missing something obvious here, but why are car purchases exempt from the threshold reduction? Dealers/dealerships must come under an awful lot of regulatory scrutiny - or pressure from elements keen to keep transactions private. Or maybe the exception applies to only person-to-person sales, and not buinesses.