Originally Posted by old,not bold
Or, indeed, penetrating the obstruction surface while landings and/or takeoffs are in progress, to be technical. But it's really ATC's job to look after that.
Hmm ... I think the Airport/Aerodrome Operating Authority actually has that responsibility. ATC are humble servants, albeit providers of professional advice which may/may not be heeded.
My local airport has operated for decades with buildings which penetrate the 1:7 OCS. Only now is that being addressed, thanks to a new Airport Director [not the SATCO].