I haven't been in the slabs for quite awhile, but when i was, there were people plying the trade, male and female. I didn't hear it talked about openly, but people knew and didn't make a big deal out of it, maybe partly because the people working were dangerous in their own right.
That said, Matt is right: there's a high probability that if you are outspoken about it, you risk attracting unwanted attention, maybe even from other sex workers.
Another thing to consider, and I hope this doesn't sound judgemental, but there is no running water in the slabs, and hygiene might be an issue amongst potential customers. My sincere apologies to anyone who might be offended by that statement. It's been my experience that many slabbers who i respect and care deeply about don't necessarily bathe regularly. This was never something I cared about at all, but as a sex worker it might matter.
Ultimately, whatever you're going to do there, you should probably go check it out for yourself for a week or two, get to know some people, get the lay of the land before becoming the lay of the land so to speak. Good luck!