The city's Erotic Service Provider's Union, which spearheaded the initiative, argues that in countries such as the Netherlands, New Zealand and Thailand, where payment for sex is allowed, sex workers are more likely to use condoms and have lower rates of sexually transmitted infections.
But in San Francisco, prophylactics are often seized, backers of the measure say. "Condoms are used by police and prosecutors as evidence of illegal activity, so sex workers are less likely to carry or use them," Klausner said.
Critics say that argument is simply false.
"Condoms are evidence that prostitution is going on, but it's not evidence against the sex worker themselves but the location of where the crime is committed," said Tim Hettrich, who retired this year as a captain in the Police Department's vice and narcotics unit. "There's no law against carrying a condom, or we'd be arresting 16-year-old boys."
Proposition K would force police to target people who prey physically on prostitutes -- including thieves and johns.
Hettrich, the retired policeman, said those risks are overstated.
"Obviously, these people are victimized," he said. "Customers say, 'I'm not going to pay this prostitute, I'm going to smack her.' But I don't think the magnitude of that violence is that high. And this new law would not stop the brothel owners and pimps from getting violent, it would help them. It'll make it harder for police to zero in on their work."