As Canadian police forces complete pilot projects assessing whether officers will wear video cameras on their uniforms, experts in both civil rights and policing say they see value in the practice but urge proceeding with caution.

"The 'how' is extremely important," Laura Berger, acting director of the public safety program at the Canadian Civil Liberties Association, told CBC News. "This is an area where the devil is absolutely in the details."

The Toronto Police Service wrapped up the 10-month test phase of a pilot project that equipped about 100 officers with body-worn cameras on March 31. The evaluation process is expected to be completed by June 30, police spokesman Mark Pugash said.

The idea of using body-worn video cameras gained momentum in the U.S. and Canada over the last few years amid concerns from both the public and the police about use of force and misconduct allegations. In 2014, U.S. President Barack Obama pledged millions of dollars for 50,000 body cameras to be distributed to police departments across the country.

In Canada, Calgary is the city closest to outfitting all of its front-line uniformed police officers with the cameras — something the police force has announced it will do by 2017.

Laura Berger of the Canadian Civil Liberties Association says body-worn police cameras can be an important tool, but are unlikly to provide a perfect solution to police violence. (Canadian Civil Liberties Association )

"This is the future," Kevin Brookwell, spokesman for the Calgary Police Service, told CBC News. "Everybody from, you know, elementary school right up to adults have smartphones or cameras. How is it that a policing agency in the … 21st century has no capability of recording what we're doing?"

The Edmonton Police Service planned to move forward on a smaller scale by distributing 60 cameras to members of its traffic services branch, but halted the program due to lack of funding, said Peter Clissold, the police service's security director and the lead for its body-worn camera pilot project.

Calgary Police Service spokesman Kevin Brookwell says about 1,000 police officers in the city are expected to be wearing body cameras by 2017. (CBC Calgary)

Clissold said in addition to funding, body-worn cameras raise a number of concerns that need to be addressed, including privacy, "because it's such new technology" that Canadian legislation doesn't specifically cover it.

"There's going to be new ground," he said. "The main findings [of the pilot project] were that there actually remained a lot of unanswered questions,"

Clissold said the pilot project in Edmonton found "no effect on the use of force," contrary to observations by Brookwell in Calgary, as well as findings cited by some police forces in the U.S.

Berger, of the Canadian Civil Liberties Association, said it's important to test assumptions in this emerging area of technology and policing.

Peter Clissold says the Edmonton Police Service is planning a gradual approach to implementing the cameras, but the program is on hold due to lack of funding. (Edmonton Police Service)

"I think there is an assumption that if people are being filmed, they will not unnecessarily use violence, that they'll be more conscious and more thoughtful about the ways that they react because they know that they're on camera," she said.

"We need to be cautious of the idea that video never lies and that video evidence will provide a panacea to concerns about police use of force and accountability."

However, the CCLA does believe police body cameras "can be an important tool for accountability and transparency," Berger said, as long as "the accountability benefits outweigh any privacy risks" for the public.

One of the key questions, she said, is determining when the cameras should be on or off, and who makes that decision.

"The value of a body camera as an accountability tool is eroded if the individual officer has control and discretion over when to turn it on," she said. "If officers can pick and choose which interactions they want to record ... we might expect that negative interactions are not going to be recorded, and so we're not going to have that evidence that could be useful in cases of police violence or in cases where complaints are lodged."

Still, Berger believes it's possible for police services to "strike the appropriate balance" with clear policies stipulating what must be recorded, including arrests, and disciplinary consequences for officers who don't have a "reasonable explanation for why there wasn't footage of [an] interaction."

Brookwell agrees, saying the Calgary police worked extensively on a comprehensive policy and will continue to revise it as new questions or issues arise.

He said situations in which officers can or should turn off their cameras include:

In a law office.

In a hospital.

When interviewing a sexual assault victim.

When interviewing a child.

Notifying family members of a death.

During bathroom breaks or while making personal phone calls.

'Tread slowly and carefully'

Police officers themselves have many unanswered questions when it comes to wearing cameras, said Bruce Chapman, president of the Police Association of Ontario.

"We're not opposed to it," Chapman said. "We see some value to it to protect our officers and … to get a full version of an event or an action where the police are engaged with members of the public."

However, "there's so many variables that cause us some concern that haven't been fully explored," he said, including whether cameras can be turned on in people's houses or in police cars when two officers are alone having a conversation.

"I just think we need to tread slowly and carefully … and have all those answers before we go full speed ahead," Chapman said.

Brookwell said that's what Calgary police are doing.

"We want to do it right. We don't want to do it fast," he said.