Quote -
I'm all for Esthers request, but given the enthousiastic reactions to it - you do know that this functionality (accept for preview) is already somewhat available for render? Turn off the visible in camera option for the object and it won't block the camera (and still be visible in reflection and for IDL calculation).

Esthers proposal is much better, but in the mean time turning off the visible in camera option is a bypass

 

This does not work if all four walls are modeled as one piece, which is common in a lot of older props and sets.