This is episode 29 named Mimikry from the successfull Czech TV-series 30 případů Majora Zemana, aired as part of the third season in 1978/1979.
Above is one of the supporting actresses, cute Ivana Andrlová playing the daughter of a police man. And in the part of the episode, where she and her friend observe some bad rock musicians, she wears a denim vest.
The rock musicians play a concert and there are some denim vest wearing women hidden in the audience. The policemens daughter, but also another strange girl with white t-shirt and blue jean vest, looking bored and grumpy and hair like wearing a whig, but not enjoying the music, compared with the most other people in the audience. And maybe some more, but only visible for a short time and hardly to catch.
After the gig, they follow parts of the band leaving the place with a public bus.
Near the end there is a short szene at the airport with another woman wearing a denim vest, but really hard to catch because fast and most time covered by an older lady.