Interesting you don't mention the tolerance zone in Vancouver, Canada. Robert Pickton murdered an unknown number of women he picked up in that zone, it is estimated at 49. He was on the bad date list.
Bad clients don't need to be weeded out if punters are criminalised and women are not. The punters are the source of the danger to women but women cannot be expected to identify which of them are dangerous and which are not.
In considering policy or law, there is a weighing up of benefit and harm. Where there is a substantial benefit to society, a degree of harm or risk of harm to some members of society might be acceptable. The less substantial the benefit to society is, the lesser amount of harm or risk of harm would be tolerated.
In the case of prostitution, the "benefit" put forward by pro-pimps is usually that happy hookers have a right to earn a living. They generally don't promote the right of men to access women's bodies for sex.
The harm, even on wino's statistics is rape, violence, murder, PTSD, mental health problems, abuse and addition which is actually happening (not just a risk) to actual women. The source of this harm is the punters and the pimps.
To me, this is a no-brainer. The "rights" of privileged happy hookers to make a living and the "rights" of men to access women are massively trumped by the real harm caused to real women. Even if I accept wino's statistics, the harm being suffered by real women in legalised environments is not being reduced to an adequate level.
The "benefit" of prostitution is illusory. Nothing will be lost by criminalising the punters and pimps and much may be gained.