We had an owner in our strata who (without permission) created a 3rd bedroom in the roof space (which is common property), along with a drop-down staircase. The committee only found out about it when he went to sell it. They called the estate agent and assured them the townhouse was a 2br, and that the alteration of a 3rd BR would have to be rectified by any new owner.
The owner removed the townhouse from sale and restored the roof space.
Were it not for a vigilant committee, that owner would have made a $400,000 (the difference between a 2br and 3br) profit and any new owner would have been stuck with an illegal renovation.