I hate to contradict a lawyer but think there's a bit more to it than that.
For instance, City of Sydney planning regulations appear to forbid the leasing of car spaces to non-residents. There's also the question of security of buildings which can be hugely compromised by allowing non residents to come and go into parking spaces.
The same section of the law has been used to try to allow short-term rentals in residential buildings and, as far as I know, has failed to do so when it has been challenged.
In my non-legal experience there are may other ways around Section 49 – otherwise we'd be saying that inner city apartment blocks can become parking stations for greedy owners.
For instance, a by-law that says owners may not operate their lot in contravention of the law – including planning law – would surely squash the parking scam.
On this interpretation, Section 49 would allow sub-letting, overcrowding, unrestricted pets, holiday rentals, brothels … whatever, because it allows free rein to the lot owner to ignore by-laws that they don't like.
Surely not? If this is the case then a lot of buildings in inner Sydney especially are going to have a lot of problems with opportunist parking space rentals.