I have a 2010 C180 Sport and found overnight it had been "opened".
I know I locked it. Has anyone heard of cars being opened? I've seen stuff around "Key Catchers" catching the signal that opens the locks but don't know if this is real....
I've seen several reports of it happening on BMWs, but none on MB's.
On BMWs it's suggested that wireless doorbells can open them randomly. (Random as in some doorbells sometimes open some cars - it's not easily repeatable).