How to tell

Dominique (stupid name for a man) Strauss-Kahn wants us to believe that he is innocent of all charges of consorting with prostitutes and accepting sex as a gift because "At these parties, people were not necessarily dressed, and I defy you to tell the difference between a naked prostitute and any other naked woman".

There are two simple answers to this not very difficult problem:

1. You ask them what they do for a living. Perfectly normal question, hardly likely to offend.
2. You see the women with no clothes on?  They are the prostitutes. Other women don't get their kit off in public to fool around in public with fat 60 year old politicians.  Believe me. They really don't. You have to pay them.  It's called Price Equilibrium.

Obviously not much of an economist.