Before her double shift at a Florida pizzeria last year, Grace Velez pulled her hair, which fell past her waist, into pigtails. What she experienced that day shocked her. Regulars who usually never tipped put money in the pizzeria's tip jar. A few older men even winked at Velez, 21, as they dropped in cash.

About halfway through her shift, the University of North Florida student began to suspect that it was her pigtails that made her tips double. She typically made $45 to $75 in tips during double shifts, but she earned $140 that day.

She made a TikTok about what had happened. The post was viewed 1.4 million times, and comments streamed in from others who had similar experiences.

The reactions were mixed — even when coming from the same person. On one hand, the reaction to pigtails, especially among men, drove home the conviction that young women are fetishized. On the other hand, the servers were making more money.

When Bella Woodard saw Velez's TikTok about how "tiptails" brought in extra cash, she decided to try it.

"If this works . . . that is so weird and gross," Woodard said in a TikTok that shows her putting her hair into pigtails before her shift at a North Carolina restaurant. "But I'm down for more tips, so it doesn't matter."

The 21-year-old usually earned from $200 to $400 a night from tips. Since switching to pigtails, her tips have increased to about $400 to $500.

Velez and Woodard have been part of a viral TikTok trend showing that wearing pigtails is a moneymaker. However, the phenomenon also has sparked criticism over how women in the service industry are tipped based on their appearance.

Although the servers' pigtail stories are far from scientific, experts aren't surprised.

"It's very discomforting," said Sekou Siby, chief executive and president of the worker-led nonprofit Restaurant Opportunities Centers United. "I have my own daughter in college working in a restaurant. She switched restaurants four times because of this type of situation."

Women in service roles are sometimes encouraged by their bosses to dress provocatively, said Juan Madera, a University of Houston professor who specializes in industrial and organizational psychology.

Madera added that "the customer is always right" mentality dissuades workers from addressing sexual harassment.

"A lot of servers see it as part of the job, that . . . they're going to be harassed . . . and sexualized by customers," Madera said.