More than likely it's the luck of the draw. They have no obligation to provide this information, and so the dealer could simply just say it's proprietary information and say "no" and give you that blank stare.
Or all could be well with the world, that day, and the parts dept or service dept guy would print out the VMI for you.
The VMI will print out by code # the dealer where the car was first sold, (ie 5758 means Calstar Mercedes in Glendale Calif) and the dealer where each warranty repair was performed. If you are *really* lucky, and the stars were aligned right, you'll find out not only that it was at a dealer near you, and all the repairs were performed at that one dealer, AND the dealer might let you have photocopies of all the repairs done there. That's VERY unlikely to happen, because they will probably want to protect the "privacy" of the prior owner (or lessor in your case), or that's the default "excuse" that you can expect to hear.....
I got actually got a VMI for mine when I was at Calstar Motors in Glendale for service, on a trip to Los Angeles (where the car was first sold) but it was my first time there as a customer for anything, so the Mercedes Gods were smiling on me that day I guess.
So, it might work for you, but you'd have to do it in person. I don't think an email would cut it.
(Although, I once bought a 4 yr. old Volvo, from a Calif. Volvo dealer, and in
the glovebox, the maintenance booklet was stamped by a Houston, Tex. Volvo dealer, and on a hunch I wrote to them, asked for all the service records on the car, and INCLUDED A $20 bill in the letter "for their trouble and photocopying expenses" and they sent me copies of EVERYTHING, even the PDI inspection, with the prior owner's name and address. Following up on that I phoned the PO, who was a Stockbroker in Houston, and he told me everything about the car while he had it, and even mailed me an extra set of keys for the car and touch up paint! Amazing. Using the same technique , I sent letters to the other 2 indep. Volvo shops in Houston who'd stamped the maintenance booklet and also, from each, received all the service records on the car they had, so I was able to reconstruct the ENTIRE service from mile zero on a car. Learned it was leased, in Texas, then turned in to VOLVO NA at lease's end, sold to an auto auction in Phoenix, where a Volvo dealer in Calif. bought it, and that dealer sold it to me 6 months later. It was VERY reassuring, after a bit of effort, to reconstruct the entire history on the car.
Using similar methods, I achieved the same thing on the 560SEC, got the whole service history with copies for all work done on the car, except the period from Dec. 1990-April 1992, on the car.)
So, it CAN be done, if you are lucky and persistent.
Jim