Tom,
Although your auction story had a good outcome for you, what you all did is termed collusion, a bidding ring, and is usually against the law. Had the seller done the same thing to drive the price up it would have been called shill bidding and folks would be screaming for his head.
Sorry Rob but I flat out disagree with you. There is nothing wrong with 2 or 3 friends going to an auction and agreeing to not bid against each other. And, it sure as heck is not illegal. Driving up a bid for a friend who is selling is wrong (and possibly illegal). But, not bidding to allow a friend who made a find to buy it is a noble thing. At least, that is my opinion. My Best Regards, Jake