Unfortunately, South Australia has rather broadly criminalised sex work. Much of the law dates back into the 1950s.
It's illegal to procure sexual services.
Get this too, say she's got a sick family member or something and she's paying for the meds with that money. That person can go to prison for 6 months, doesn't matter if they have any idea where the money's coming from.
If the letter of the law is followed without discretion, anyone who that money touches goes away.
Also, being illegal in SA means no state gov mandatory health and STI screening.
For comparison sake, up in Qld, I get pulled over for a random breath test. The officer asks where I'm headed and I say I've got 2 girls booked for an hour at the local brothel. He says have a good night sir and I'm back on my way.
Infact only SA & WA has criminalised sex work.