I do not remember to have seen one of freiwilliger Durchgang when I first went to Vienna, but I had seen it (probably would have gone over), you usually do it unless you have been invited, not in the palaces of others!
And I wrong because freiwilliger Durchgang purpose of Vienna, is precisely to allow others, pedestrians, non-proprietary or non-residents, to go through courts and courtyards of the buildings, creating, in fact, the real shortcuts of all the inner city due to the high range of the nice apartments in Vienna. In short, the meaning of these doors is just to say, “if you want to come in and go from there“.
These steps, a sort of dead, were born at a time when Vienna was developing rapidly, without a real plan. It was a response dictated by common sense, the need to cross the city without having to, to make a long and tortuous path. With time, this need did fail and Freiwilliger Durchgang began to disappear (but I understand it now, somehow they were “protected” from the town hall).
This photo is of Raimundhof, perhaps the most appreciated by the architectural point of view, which is now a real alley, with lots of bars, restaurants and shops, including a jewellery store. Here stadtbekannt.at (in German) is the list of Freiwilliger Durchgang of Vienna.
Photo:lembagg