Reed Nyffeler, director of sales and marketing at Omaha-based Signal 88 Security, said his firm had received dozens of calls from local stores since Wednesday inquiring about stepped-up security measures.
The holiday season is especially challenging for mall security because of the throngs of shoppers, making it difficult for employees and guards to keep track of potentially suspicious people, he said.
Nyffeler estimated that, nationwide, only about 5 percent of mall security officers are armed.
"We function mostly as a visual deterrent," he said. "Our intent, even with the armed security, is not to apprehend. It's to profile and deter."
Andy Miller, an Omaha resident shopping Friday at a mall near Von Maur, doubted that adding more guards or metal detectors would have much impact - except possibly to inconvenience law-abiding customers.
"That would be a waste of time," Miller said. "He could shoot people out in the parking lot. What difference would it make?"
Ellin Bloch, a Los Angeles-based psychologist who specializes in traumatic stress, suggested that most Americans would oppose more intrusive security at malls.
"People really want to have a feeling of some freedom," she said. "We have an illusion that we're safe, and we have to retain that illusion, just for the sake of survival."
Bloch's sentiment was echoed by Josh Husk, whose grandmother, Janet Jorgensen, was among these killed on Wednesday.
"You can't live in fear," he said. "You have to live every day like it's your last."
Associated Press writers Eric Olson in Omaha, Justin Pope in Raleigh, N.C., and Travis Reed in Miami contributed to this report.