It is a real problem for Audiogon. I do think the reason is financial, and they must have some evidence that sales are made outside of their system.
The issue with charging more up front is for people like myself who try to run at least one ad at any one time, in a year like 2011 when I had no sales, I would have lost a great deal of money, and need to stop advertising. I support Audiogon in their attempt to keep the cost of placing an ad down and affordable, I do not support losing the ability to enjoy other members without a moderator.
Perhaps if they did not censor as much as they do, then the need to converse directly would lessen, but then you get the "cables don't matter" guys interrupting what might be a real conversation, so that is a dumb idea on my part.
It's a tough spot for Audiogon, and unfortunately they took the wrong route and ended what was an important part of this community.
Here's a bizarre idea, how about Audiogon trust people and have them not feel the need to cheat the system if that is indeed happening, which I doubt is the problem they have made it into...
JD