i agree but digressing slightly in a past life i had to deliver a 2 year old volvo s8o (so was a while ago) back to a lease company.
when arriving at there headquarters was told to pick a spot on the field at the rear to park it.
to my surprise there must have been nearly 200 parked up all around 2 years old.
when i quizzed the manager over it , someone in purchasing screwed up and leased them from volvo at a set mileage over the term. then re leased them on contract to a major uk bank at nearly double the mileage....oops.
hence it was cheaper to bring them in at just below the mileage and park them up, for 12 months , and re lease another vehicle than be stung with extra mileage charges from volvo.
seemed crazy at the time but he showed me the figures and it saved them thousands to do it. plus they were as straight as a die company so would doubt even in days if mileage adjustment would even have been on the horizon.
maybe this merc was on its mileage target and merely parked up, .
or maybe last owner deceased and stuck in probate... bought many cars from next of kins when probate granted and lots were stationary for a while always had to service or have serviced if new enough to get dealer or a stamp in the book. also had quite a few expensive repairs as well through standing so if its not exotic always find another one.