Considering that Mercedes roadside assist does not include unlocking service, you may not be making out badly at all. Once when I was working on my '87 300D Turbo (W124, OM603) I managed to lock the only keys in the car. Mercedes told me (via telephone) they would have to charge for opening the door so I had AAA do it for free. (They too used a plastic wedge and then a slim-jim. Didn't hurt the car at all and I now have several extra keys.)

According to the owner's manual, the Mercedes web site, and everything else I've ever read or heard about the roadside assistance program, the free service is limited to:
1. Start the car (up to 1 hour effort)
2. Bring fuel (customer usually required to pay for fuel)
3. Install customer's spare tire
Anything else including getting into the car is charged at 150% of the dealer's normal rate.

Even so, the service guy didn't have to be a jerk. I think you're lucky that the dealer wants to be friends.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970