Heard an interesting story here in the UK the weekend from a sales guy at a dealership. They and maybe others sometimes do or used to rent out cars for people to use. Someone paid for a new Z4 M Coupe for a few weeks. The car returned in a right state and with thousands more miles on it. The dealers found pictures of it in the Gumball rally! Another reason to be wary of ex-demonstrators/dealer cars.
Did the course at Mugello in 2006, lead to me buying my first Z4MC . Apparently ex fahrer training cars are sought after as they are so well maintained. At the course they had mechanics on site and an artic load of tyres from Michelin.