A day after Manitoba Liquor & Lotteries first announced it will soon require people to show photo ID to enter its stores, civil liberties experts say the Crown corporation will need to tread lightly in enforcing the new protocol.

Liquor stores making sure customers are of legal drinking age is business as usual, said Michael Bryant, executive director of the Canadian Civil Liberties Association. But if the policy involves denying adults entry or collecting their personal information from their IDs, it would constitute a rights violation, he said.

"There's no way that they should be able to swipe people's ID cards or driver's licences, because then they're going to be getting data that goes way beyond whether or not the person is the legal age," said Bryant.

"It's just, 'Are you the legal age or not?' Period. And anything more than that is an abuse of power," he said.

The new security plan was already in the works, but was fast-tracked after a violent robbery at the Tyndall Park Liquor Mart Wednesday that sent an employee to hospital in critical condition when she was knocked unconscious.

Just how far the security measures will actually go remains unclear. In a statement on Thursday, Manitoba Liquor & Lotteries said all its Winnipeg stores will be retrofitted with controlled entrances, and customers will be required to show valid photo ID at a security station before being allowed inside.

The statement did not say whether any data would be collected from customers' IDs as they enter the store. The Crown corporation declined to do any interviews on Thursday, saying it was inundated with media requests and trying to focus on employee safety after Wednesday's Tyndall Park assault.

"While we are aware that not sharing information details about our initiatives leads to criticism and accusations of inaction, we make this choice deliberately, as doing so could compromise our security efforts, providing valuable information to would-be thieves and putting our employees and customers at risk," the statement says.

Changes must be evidence-based: expert

Katharina Maier, an assistant professor of criminal justice at the University of Winnipeg, said increasing security is a common response to violence — but she cautioned against thinking the new measures will solve the problem liquor stores are facing in the long term.

"If it was that easy, then we wouldn't see crime and violence happening in other contexts and places, because we are actually a fairly high-security society. So clearly security is not the answer, or certainly not the only answer, to dealing with this issue," she said.

"They might temporarily kind of deal with the issue, or displace it somewhere else."

Civil liberties director Bryant said it's important for any security measures to be based on evidence — not just "speculation and fear."

"Is the new security measure being introduced proportionate to the actual risk of there being a robbery or property damage taking place in the Liquor Mart?"

Numbers from the Winnipeg Police Service show that robberies — which are distinct from thefts, because they involve violence or threats — make up a relatively small proportion of overall thefts reported at Liquor Marts across Winnipeg over the past year.

Michael Bryant is executive director and general counsel for the Canadian Civil Liberties Association. (Jacqueline Hansen/CBC)

From March to August of this year, there were 1,065 theft incidents at Liquor Marts where at least one person was charged. During the same period, there were 31 robberies.

The ratio is similar stretching back from September 2018 to August of this year. During that period, there were 2,075 theft incidents at liquor stores where at least one person was charged, and 105 robberies.

Bryant said as a Crown corporation, the onus is on Manitoba Liquor & Lotteries to make sure people are informed of their rights as they try to enter the stores when the new measures are in place.

"They have to be at least doing as much public education as they are advertising to get people to come in and buy the booze," he said. "People shouldn't go in to the [secure entrances] wondering what's going to happen and what their rights are."

Winnipeg Police Service spokesperson Const. Rob Carver said at a news conference Thursday the police service is supportive of the new measures coming to Liquor Marts.

"It has some definite merit," he said. "I think it presents a barrier for somebody who is looking at attempting to do what would start out as a shoplifting and possibly end up as an armed robbery."