Credit union staff members who supported the installation of the windows also noted the threat from members outside the USC community who might use the branch, located above Café '84.
"We're so close to the main street, they could just walk in," said Scott Rains, executive vice president of the USC Credit Union.
He also said he does not want members of the community doing their banking on campus.
"It's not good business for the campus," he said. "We're building an off-campus facility southeast of the campus to serve the community."
Community members not affiliated with USC and USC students have been eligible to become credit union members for the past four or five years, Rains said. Before then, only USC faculty and staff members could join.
The credit union branch at the Health Sciences Campus located just east of downtown was held up late last fall by two robbers, at least one of whom brandished a gun. The perpetrators "got away with almost nothing," Rains said.
The robbery investigation was turned over to the FBI, which recommended the installation of the bullet-resistant windows, Rains said. The Health Sciences Campus credit union branch has had the windows since late December.
The Department of Public Safety "heartily endorsed" the windows, Capt. Joe White said.
"Most banks have gone back to putting in separations," he said. "When they put in the 'bandit barriers' it really negates the crimes. It makes all the employees feel a lot better."
Some customers noticed the new windows the hard way by accidentally banging their foreheads against the fiberglass. Customers trying to get used to the change have also yelled at the bank tellers, thinking the barriers were soundproof, said Robert Yuniskis, a credit union teller.
"You don't have to yell," he said. "As far as security devices go, they're attractive."
Yuniskis, who has worked at the USC Credit Union for 14 years, said he never felt unsafe in his job but thinks that the barriers help reassure the staff.
But some customers have worried that the barriers signal an unsafe environment and make the branch impersonal, he added.
While acknowledging that the windows require some adjustment for customers, Rains pointed out that the windows are a deterrent to robbers.
"It's for everybody's safety," he said. "It's much easier for the bad guys to go somewhere where they don't have (the windows)."