In a con like this one, the social engineer tries to pick a target who is likely to have limited knowledge of computers. The more he knows, the more likely that he'll get suspicious, or just plain figure out that he's being manipulated. What I sometimes call the computer-challenged worker, who is less knowledgeable about technology and procedures, is more likely to comply. He's all the more likely to fall for a ruse like "Just download this little program," because he has no idea of the potential damage a software program can inflict. What's more, there's a much smaller chance he'll understand the value of the information on the computer network that he's placing at risk.