Correction
Three girls are going out of school. A teenager calls one of the girl by her name. She doesn't seem to know him. She seems surprised. A few minutes later, when crossing the sport ground a coach calls the girl by her name again. Then , when going to the cinema with her boyfriend, Sarah is really embarrassed when the man asks her what colour underwear she wears today. At the canteen , an employee asks her whether she is going to post something new;
No doubt Sarah belongs to a social network / Sarah must belong to a social network and must have posted private pictures of herself since everybody recognizes her. The photos may have been posted by somebody else too.
The document is a short video. It is an informative commercial to warn / to prevent people from posting on the internet. People should be careful before posting because family, friends, anybody can see.
I think......
If this girl is taking revealing pictures of herself and putting them online for people to look at, it is doubtful that she is innocent!