In any type of business the idea is to make it as easy as possible for the customer to buy the product. In my opinion, girls selling their time/services also need to do the same especially with so much choice out there.
I always like to ring a new girl for a chat before we confirm a booking, but I've never paid for the chat.
I mentioned a while ago that there were 2 girls locally to me who insist on seeing a punter's pic before they'll agree to a booking.. one has been on adultwork for over a year and still has zero feedback.
Another girl insists that her husband is in the same room for her safety.. but he won't join in unless requested
Make it too difficult, and the punter will go elsewhere.