Do you know what this mean?

Most likely it's a deflection - she is not welcoming the fact of being looked at.

Young women get "looked at" everywhere they go.
Often those looks are distinctly predatory, indicate a stranger about to make a move - shoot a line, an inappropriate invitation, a sexual insult.
If rejected, the stranger instantly becomes nasty and insulting.
Common behaviour in big cities.
Young women get absolutely sick to death of being regarded as a sexx object and feeling unsafe while simply travelling to and fro about their normal lives - as students, workers, shoppers or mothers.
Smart young women learn an arsenal of defences to deflect men: picking the nose, eating raw garlic, avoiding eye contact, hoodies, the list goes on and on.