I do understand very much the paranoia. There are so many people that just don't care. Even if it didn't hurt it(which it does) to do a bleach burn out, it's not their car to abuse.
This won't make you feel any better, but I went by the MB dealership where my X-brother-in-law works as a tech. He told me when I was leaving, to take note of how short the freeway entrance ramp was. He said that an SLK would hit 120 before the end of it. I didn't know the SLK's were that quick. I would love to have one, but if I ever needed service work, I'd make sure he didn't test drive it.
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in