TORONTO - It's common sense that anti-prostitution laws put sex workers in danger, and taking them off the books has the potential to save women from killers like Robert Pickton, a lawyer in a landmark appeal said Wednesday.

The federal and Ontario governments are trying to overturn a decision that struck down the laws against keeping a common bawdy house, communicating for the purposes of prostitution and living on the avails of the trade.

Superior Court Judge Susan Himel ruled they were contributing to the danger faced by prostitutes by forcing them to choose between obeying the law and keeping themselves safe.

A group of sex-trade workers are arguing that the laws prevent them from working indoors where it's safer, taking time to talk to a potential client to assess the risk they pose and hiring bodyguards.

Their lawyer, Alan Young, told the Court of Appeal for Ontario it's hard to imagine any legislative objective that is commensurate with the harms faced by sex workers as a result of the laws. Court has heard from government lawyers that the laws are in place to deter people from entering prostitution.

"This is ethically unsound," Young said. "No government should be able to jeopardize the safety of its citizens just to send a message."

A blanket prohibition on conduct that can enhance the safety of sex workers defies common sense, Young said.

It was an assertion that Justice Minister Rob Nicholson once appeared to agree with before he was the minister, Young said, quoting from a transcript of a 1985 legislative committee on amendments to the law prohibiting communication for the purpose of prostitution.

"It seems fairly logical to me that out on the street or on a dark street or in an alley or in a parking lot, that is perhaps where people are most vulnerable; that they may be less vulnerable in hotels to violence," he said, according to the transcript.

"Do you not agree that maybe the street corner or the alley or the parking lot may be more dangerous, for instance, than the bars or the hotels or the small brothels?"

During federal government submissions on Monday, the five-judge Appeal Court panel closely scrutinized Ottawa's position that the laws aren't putting sex workers in danger, grilling the government lawyer.

Young, who had an easier go than Ottawa's lawyer, still had to spend time Wednesday defending against questions from the judges about who would actually benefit if the laws were off the books.

He challenged the governments' assertion that most prostitutes are in the trade involuntarily and would leave if they could, but said in general sex workers who choose to ply their trade would benefit from being able to work indoors and hire bodyguards.

Still, he said, "even if one person moves indoors and as a result doesn't end up on a pig farm...then something good has happened."

Pickton was convicted of second-degree murder in the deaths of six women. The remains or DNA of 33 women were found on his Port Coquitlam pig farm, and he bragged to police that he killed as many as 49.