DERF, my gut reaction was the exact as yours ie multple aliases coming in & using the resources here for free but then then I thought that freebies have the use of the resources anyhow so where is the theft? It has been my experience that the only way to prevent something is to make the end result for the person(s) causing the discomfort or affront, an unpleasant one. For example, someone gets a rush out of stealing from you, so you make the act of stealing from you an unpleasant act. A disincentive if you will. A Trojan Horse. For example, in South Africa there was a serious problem with car jacking. So a couple of enterprising individuals came up with a novel way to prevent them. They equiped their cars with flame throwers such that when confronted by a carjacker, the driver merely pushed a button & flames shot out from the side of the car incinerating the carjacker. That person didn't carjack anymore.