[wim]

Shutter being closed as the lens is off is an awful idea. One misaligned lens or adapter or one slip of a finger and your shutter is gone whereas an open sensor would've been fine as it'd be burried significantly deeper and much better protected by the light baffle around it.

And it's much cheaper and easier to change a sensor glass than a shutter. Also keep in mind that a scratch or dust on the sensor is not really such a big issue while a damaged shutter is.

?

How would you misalign a lens or adapter, or even slip a finger to touch the shutter, even with a shutter "only" lying, say 18 mm (taking it conservatively, it probably is 19.5 mm) deep into the body?

You won't be able to stick a lens or adapter that deep into the body, not even when holding it perpendicular to the camera mount. And I really wonder how one has to hold a lens or adapter to accidentally stick it into the body so far that you'd actually touch the shutter with a finger. Surely your fingers are around the lens well before the mount as you'd not be able to mount the lens at all. Besides that, the shutter is very flexible, and can handle more force than you might think.

BTW, have you ever inadvertently touched a mirror in a dslr or slr, with finger(s) or lens? That is very easy to touch compared to a shutter in a mirrorless camera. Shooting slr's since 1973 and dslr's since 2005 I personally have never managed to do so.

In short, IMO, this is just scare-mongering, and effectively a total non-issue.

Kind regards, Wim