The renovation contractor of my apartment once said that he did some renovation works in some condo in Mont Kiara. He said that the people there are generally high class as you can't hear any noises from the units. Pin drop silence even when some families have kids. Perhaps it is another form of judgment to determine whether the apartment is high class apart from the value of the property - the noise that the dwellers make. Low class apartments usually mid to low cost ones are quite a bit noisier with shouting kids or adults alike, making loud noises in their units etc.