Ritter and the sisters have joined other groups in pressing hotels to train their staffs.
Housekeepers, desk clerks and security guards learn potential signs of sex exploitation: A bar code tattooed on a girl's neck. A "Daddy" tattoo. Repeated calls from the room for extra towels. Alcohol and teddy bears. Alcohol and ice cream. A coil of rope. Blood on the bed.
Even for hotels willing to help, however, it can be tricky.
"It's a very fine line," said Dieter Heigl, the general manager at the Marriott O'Hare, where staff are told to be on the lookout. "We're in the hospitality industry and you can't go around accusing people."
The first step toward solving a problem is making people aware there is one. The Sisters of St. Joseph educated Ritter and she, in turn, educates hotel employees.
"It's women helping women," she said.
Ritter and the sisters extend that attitude beyond their work against sex exploitation, knowing that cultivating respect for women is a cause with many interlocking pieces.
Last week, Ritter accompanied the sisters as they did something that no conventioneers had ever done at the Marriott O'Hare. They asked to visit the housekeeping staff.
The women who change the sheets and empty the trash gathered around, and the sisters said, "Thank you."