Picnics in Minneapolis parks have all the usual fixings: sandwiches, fruit, maybe some pretzels.

But many people noshing while watching a movie in the park or listening to a concert at a band shell also bring liquid contraband, barely disguised. There's someone swigging from a beer, its label concealed in a can koozie, someone else sipping wine poured from a Thermos.

Drinking on the sly may not be necessary at Minneapolis' newest park, the Commons in front of U.S. Bank Stadium, if a proposal to allow parkgoers to bring their own booze during certain events prevails at City Hall.

That would mark a shift from rules in Minneapolis parks, as well as others across the metro, which bar alcohol except when it is served at concessions and events with special permits.

"Being able to sip a glass of wine on a picnic blanket in a park is cool and fun," said Council Member Jacob Frey, who is pushing the measure. "And you want to attract and retain talented millennials to a city. These small changes are the kind of things that get you there."

Officials have already been quietly relaxing the rules for alcohol in Minneapolis parks. Concession restaurants like Tin Fish and Sea Salt have been allowed to sell beer and wine for more than a decade. New rules approved by the Park Board in 2013 expanded where permits could be issued for alcohol-serving events — and nixed a ban on alcohol possession. But casual picnicking allowing BYOB is not legal.

Still, data show that police are citing fewer people for common alcohol violations at parks and parkways across the city. Such offenses have fallen by nearly 30 percent since 2011.

There were just over 400 citations, including some arrests, in 2015 for calls in which the primary offense was alcohol in a park or parkway — vs. an assault with an added alcohol offense. Nearly all of those occurred on land governed by the city's independent Park Board, and its Park Police, but the figure includes some plazas controlled by City Hall and Minneapolis Police, like downtown's Convention Center Plaza and Peavey Plaza. The Commons is the first major park operated by City Hall.

Park Police Chief Jason Ohotto said officers also give warnings, but, "The more advanced enforcement tools like a citation or an arrest happen when the systemic behavior is causing some sort of disorder or chaos."

A tangle of rules

Alcohol rules vary widely across the metro area. St. Paul allows people to drink booze with less than 3.2 percent alcohol in 12 designated areas, and events can also secure temporary liquor licenses to serve regular alcohol.

Many park systems such as Golden Valley, Maple Grove and St. Louis Park bar alcohol altogether — with some exceptions for certain permitted events and rented facilities. Others are more relaxed: Woodbury, Apple Valley and Three Rivers Parks District generally allow people to bring their own beer or wine.

"For the most part, we don't have a lot of issues," said Lynn Stoltzmann, director of facility services for Three Rivers Parks District. "But when we do have an issue, it's usually related to underage drinking."

Minneapolis prohibits bringing alcohol into parks without a permit. Permitted private events at designated areas, like picnic shelters, can have 3.2 percent alcohol. Serving regular alcohol at a private or public event generally requires having Park Police present.

A Star Tribune analysis of police data showed that six park areas accounted for about half the citations and arrests in Minneapolis since 2011: Hidden Beach at Cedar Lake, Loring Park, Lake Calhoun, Washburn Fair Oaks Park, the western riverfront area near the Hennepin Avenue bridge, and Franklin Steele Park. By contrast, about 10 were given out at Lake Harriet, which draws huge crowds for nightly events in the summer months.

Ohotto said officers' goal is to prevent the larger problems that can accompany alcohol use. For example, at Hidden Beach, officially known as Cedar Lake East Beach, the secluded scene makes it a trouble spot for more serious incidents, including overdoses, medical emergencies, robberies and assaults.

"The common denominator with all those crimes is impairment from alcohol," Ohotto said.

Or as Jeanette Colby, chairwoman of the Kenwood Isles Area Association, puts it: "It's not a beer or a glass of wine that causes problems. It's the fifth of vodka."

Drinks at park events?

Scott Vreeland, the park commissioner who sponsored the 2013 change to Minneapolis park rules, said it has worked out well. He highlighted the city's Arbor Day celebration at Logan Park, for example, which had a beer garden featuring local breweries. That wouldn't have been possible under the old rules, which restricted alcohol to specific locations.

"I think it's made a lot of music and community gatherings more fun and interesting," Vreeland said. "At least for me, who loves IPAs."

He said the rules make it possible to deal with problems.

"I think what we want is people to be well-behaved," Vreeland said. "And if they're sipping a beer and not bothering anybody, is that really a problem?"

The proposal to allow some of what Frey calls "BYOB or W" in the Commons may get its first hearing at City Hall in coming weeks. It would echo rules in another major city's downtown park, Chicago's Millennium Park, where visitors can bring alcohol to the pavilion area during events.

Frey said he already sees people drinking wine during movies at Gold Medal Park. He said the limited changes at the Commons would be a first step that should be monitored to determine if it should be expanded in the future.

"The ability to sit, watching 'Indiana Jones,' slugging a can of beer or a glass of wine and enjoying community, works," Frey said. "It works on the Seine in Paris and there's no reason why it can't work on a limited basis in Minneapolis."

Twitter: @StribRoper