RICHMOND HEIGHTS, Mo. — Chaz Brewer visits the upscale St. Louis Galleria mall about once a week, checking out clothing stores like Aeropostale and American Eagle and hanging out in the food court.

But come April 20, he can't visit the mall by himself on a Friday or Saturday night, under a new policy that prohibits teens 16 and under after 3 p.m. unless they have a parent or guardian with them.

Brewer, 16, doesn't plan on cruising the mall on a Friday night with his mom.

"That's like a party pooper, for real," he said.

Teenagers across the nation are facing similar dilemmas. Malls looking to restore what they call a family-friendly environment are putting policies into place requiring that younger teens have adult supervision during certain hours, almost always on the weekend.

Mall officials say the policies cut back on unruly behavior and loitering that can turn off other shoppers; teens charge they're being singled out for the bad behavior of a few.

At least 40 malls out of 1,100 in the United States have put teen curfew and escort policies into effect. The majority of those policies have started since 2004, according to data collected by the International Council of Shopping Centers, a New York-based shopping center trade organization. The organization said it could not predict if more policies will be put into place.

In the malls with the policies, security is usually stationed at doors or throughout the shopping center on Friday and Saturday afternoons or evenings. Teens who are not escorted by an adult, usually 21 or older, are asked for identification. If they can't prove they're old enough to be alone or that they're with an adult, their parents are called to pick them up. If the kids refuse to cooperate, police could be called.

"These policies are not places saying they don't want teens to shop in their centers. They're saying: 'Bring a parent to shop with you,' " said International Council of Shopping Centers spokeswoman Patrice Duker.

Malls say the policies are improving the environment on weekend nights. Some report that stroller rentals are up on weekend evenings, a sign that families are visiting in higher numbers.

The enormous Mall of America in Bloomington, Minn., with 520 stores, has a policy that's about a decade old it calls incredibly successful.

There used to be times when thousands of unescorted kids arrived at the mall on a weekend evening, said spokeswoman Anna Lewicki Long. Instances of teens arguing, spitting or hanging out without supervision were making it uncomfortable for other shoppers, she said.

With the new policy, the mall no longer feels like it's a baby sitter. Additionally, it has at least doubled the number of stores that cater to teens, with more than 75 now on site, she said.

Several mall officials said no one instance led to beginning the policies.

The Galleria, for instance, had fights break out on both Nov. 11 and March 3. A police report from November refers to a "large crowd of approximately 50 subjects fighting and screaming in apparent riot-like behavior," involving both teens and adults.

Richmond Heights city and police officials said they're supportive of the mall's new policy, but hadn't asked for it. The Galleria draws millions of visitors annually and normally runs smoothly, they said.

Chicago-based General Growth Properties, Inc. which owns and manages 220 regional shopping centers including the Galleria — and Ala Moana Center — said three of its malls have parental escort policies and they're in the works at two others.

The majority of code of conduct violations at the mall, which are not reported to police, are issued to younger shoppers. Those violations include things like running, swearing and loitering, said spokesman Kirk Ballard.

"Where we have implemented it, we have seen extremely dramatic results," he said.

At its Columbia Mall in Columbia, Mo., security used to note about 50 to 60 instances where people were asked to correct their conduct on an average Saturday night. That's dropped to about five to eight conduct corrections a Saturday night since a similar policy went into effect there.