Something similar in my old complex of townhouses. The construction meant that the garages and entrance ways were on one level, and the living areas were half a level up and behind. So behind the garages/entrance ways was the foundations for the living areas, sitting on mostly rock and a drainage line that ran the length of the complex. Owners thought they could do what they wanted – concrete, dig out, storage area with build in shelving, wine cellars, boat storage, teenagers retreat!!! Some even advertised this area when put on the market. But, of course, they all wanted the OC to pay when something went wrong with the area – foundations moved, water build up, mould.
I did try to point out that this was wrong. But, as usual, I was ignored – because they all had stars in their eyes thinking of the extra space they could have for nothing!