Clementine Crawford had a favourite restaurant in New York that she liked to eat alone at at the bar. After some time, she was told she couldn't sit at the bar and was moved to a table, and when she asked why, she was told there was a 'crackdown on hookers'. The BBC article
(which also seems to be an advert for the three individuals' careers) has anecdotes from two other women who have experienced similar.
I'm not sure what the article is trying to say when it asserts that most women have a vague sense of vulnerability when eating out alone. I do too until I am actively munching on my food, and even then I'm hoping the waiter/tress doesn't ask me how is my food mid-mouthful as they always do. Waiting to be seated, waiting to order, waiting for food and waiting for the bill mean you're depending on someone else to do what you're not certain they're doing. I don't worry about being suspected of being a prostitute, though, but then I don't imagine I wear the same outfit as one as Gloria Atanmo apparently did in Rome. I don't think feeling vulnerable when alone in a restaurant is exclusive to women, and certainly not messing about on your phone as a 'shield'.
Have you been mistaken for a prostitute? I've been mistaken for a smoker (many, many times), a drug user (a few times) and by a prostitute as a potential customer (twice) just walking around. Perhaps I looked like those things on the day, or perhaps I was just randomly asked as one of many for simply being in the vicinity of the person asking.