I don't think there is much point in newspaper ads now. They were always very basic with no real information on cost, services or looks... but then if adultwork has an extended blackout or the internet dies, it's good to have a backup plan.
I think that the Internet is only a small part of the marketplace. As we use it and know our way around, it is easy to think it is the heart of finding good punts but we know that so many profiles are faked, message and phones not answered and B & S on the front line. This can easily occur because the advertising is free.
The Echo, Mail and Bargain Pages all charge, a decent ad in Bargain Pages is about £700 for three months. I would suspect that neither girls or Sergei would fork out that sort of money if they were not going to pick up the phone or have a reasonable chance that when a punter gets through the door he will pay up and stay.