I almost got scammed into buying wipers at a gas station. How about you?

I recently had an experience at a gas station in Gangnam. After finishing refueling and getting ready to leave, someone approached me and said that my car's wiper seemed to be malfunctioning. They used the expression '나와 있어요,' and I was puzzled because I had just replaced the wiper a week ago. At that moment, I was too busy to check, but when I got home and took a closer look, the wiper was perfectly fine. Upon further investigation, it seems that there are people who often try to get others to replace their wipers in this way. Have any of you had a similar experience? I'm particularly curious if you've encountered this in areas with many foreigners, like Itaewon or Hongdae. How should one handle such situations? I would appreciate your advice.