Having carefully written down the mileage on her sporty black BMW's odometer and day trip mileage counter when dropping off the car August 11, she compared those figures at pickup on August 22 expecting a near match.
"But it is off by 724 miles!" exclaimed Gunthart. Asked what to make of that, she replied "somebody had a nice vacation other than us."
To put it in perspective, 700 miles is a round trip to Buffalo from JFK or three round trips to the Hamptons and then some.
"I was flabbergasted," said Mimi's husband Ulrich Gunthart. "Totally surprised. Couldn't believe my eyes."
It all reminds us of that classic 1980s film moment in "Ferris Bueller's Day Off" when Ferris's friend Cameron realizes the car they'd left in a lot -- Cameron's father's car "borrowed" without permission -- had been joy ridden all over town by parking attendants. Ferris discovers the truth when he checks the odometer.
"We investigated and reviewed our inventory logs and found nothing out of the ordinary," responded Avistar Regional Manager David Menter.
Except maybe for the new ink stain that the Gunthart's say they spotted on the front passenger seat. And a CD that was suddenly blasting when they turned the car on.
"There's no chance we got the calculations wrong, not with both of us doing them," said Gunthart.
"Hopefully it's a weird isolated thing," said parking manager Menter, who added that there were no previous claims by any other customers of mileage mishaps. Drivers are required to leave keys with cars and tell attendants how long they plan to be away.
Avistar and the Guntharts agree that in the future customers and attendants should both sign valet stubs indicating the mileage at drop off, according to Menter.
"We're definitely going to be examining the procedures to make sure that there's never any question in a customer's mind in the future," said the manager.
That could affect the Guntharts, who plan to leave that BMW at Avistar again the next time they fly out.
"There's no way it would happen to our car again, not after this attention," said Ulrich Gunthart, who added that -- other than the 700 miles situation -- he thought the service and prices were quite good.