Mercedes Transmissions

[Alan Hamm]

Been wanting to ask this for some time.

For some reason, perhaps because I can, I often shut my Mercedes cars off with the cars in Drive. And because I can, I remove the key without putting the car in park. And then the cars starts to roll.

1. If left unchecked, how far would it roll?

2. What caused the transmissions to disengage when the engine is off? Is this controlled by vacuum?

3. How is this good? Why would they be like this? Seems dangerous, unless there is a certain distance where it rolls before it catches. I have not wanted to test this, but I have been half way out of the car and had to jump back in and hit the brakes.