A guy on the phone saying he's anon361 or El Gordo could be anyone, but if the booking is by pm then the lady can be pretty sure that it's you or me. A lot of escorts who are active on the boards prefer pm bookings. Aside from safety, it decreases the chance that it's a timewaster. It doesn't eliminate it, since some well known posters are known to be serial timewasters. For a while Karin was offering a discount for pm bookings. She had to stop because too many clients found the concept difficult to understand.
ps Ladies, if someone who hasn't sent you a pm says he's me, he's almost certainly lying.