If you’re on a boys night out, and they have brought you ‘to a cool place’ then you are probably in a borello so there is a good chance you will be able to tell..
The truth is you can’t.
Somehow prostitutes are the modern equivalent to when people would be looking for the wart, hat and broomstick to tell a person was a witch.
It may come as a strange fact but people in the sex industry are normal average people outside of work.. just like everyone else is. They are mothers, fathers, sons, daughters, friends, students, etc etc.
Walk down a street and look at the men and women you pass. The things is you just may be looking at one or two people doing sex work. But it wont be the stereotype person you think it should be. A job doesn’t make someone suddenly something else. Try working out which people are teachers, nurses, office workers, accountants. Unless they are in uniform you will have the same difficulty.
My question is Why would it matter to you?
Unless you’re actually looking for one to spend time with, would you care or need to be able to tell if someone was a worker or in the adult industry or not.