Even for malls still in development, security measures are part of the planning. For example, construction is expected to begin next spring on Empire Outlets, a 340,000-square-foot retail center planned for Staten Island, yet the developer is already weighing security issues. The complex, designed by SHoP Architects, will include 125 outlet retailers, restaurants, cafes, a 200-room hotel and a 1,250-space parking garage.

BFC Partners, the mall’s developer, is considering ways to incorporate smartphone technology into its plan. In addition to security guards, the mall will have hundreds of security cameras monitoring the complex.

“We have been thinking about security from Day 1 of the design process,” Joseph Ferrara, a principal at BFC Partners, said in an email.

Malls play a curious role in American society. There are 115,616 retail centers in the country, according to CoStar, a real estate information company. Privately owned and operated, many of them have become de facto downtowns that house post offices, banks, indoor playgrounds, churches and, in some cases, a satellite city hall.

Civil liberties advocates worry that if American malls turn into fortresslike structures where shoppers are profiled and monitored at all times, the places that double as city centers will become tightly controlled by private businesses that would profile customers continuously.

“Main Street has moved to the mall, but the First Amendment rights that accompanied the public spaces didn’t accompany them,” said Jeremy R. Nemeth, chairman of the department of planning and design at the University of Colorado, Denver. “A lot of mall security is predicated on limiting who uses the space and not just how you use it.”

Security systems and improvements are expensive. A closed-circuit television security system can cost hundreds of thousands of dollars to install and maintain, and much more if malls want to overhaul existing systems for newer, more sophisticated technology. Software and cameras can track bags left behind, count people entering and exiting through doors, and detect when a person has entered a restricted area.