It's not rape if both parties consent to the act. I'm not sure if it would considered theft, since the act of prostitution is illegal in most places. So can you break a law about breaking a law? Since actually giving the sex worker the money would be the crime, not giving her money would actually keep you safe. Since you could honestly tell the police that you didn't pay that person for sex. Regardless, it's a dick move to do. That person has a job, and sometimes it's not a pleasant one, and they do it to live. Not paying them the agreed upon remuneration makes their life harder.
I've never understood the cultural behavior to treat sex workers like sub-humans. What's wrong with a job that gives people orgasms? I fail to see how a higher number of people with access to stress relief, happy endorphins, and some physical intimacy is a bad thing. As George Carlin put it once "Of all the things you can do to a person for money, giving them an orgasm is hardly the worst thing. Why is it illegal to sell something that's perfectly legal to give away?!"
We applaud, and try and hero-fy blue collar work as being "good old fashion work, that keeps the country going!" And yet prostitutes are somehow less than human, and worthy of nothing but scorn and derision. And hey, it's ok right? She's just a whore right? Who fucking cares? It's not like she's a person or anything.
Fuck that noise.