Here’s my thinking: Scarcity is a big factor in people’s desires. Behavioral science tells us that when someone thinks a resource is scarce they will want it more. For a startup, getting resumes from college kids when competing with big names like Google and Facebook is incredibly hard. Very few want to take the risk of joining a startup, or even understand what that risk is, or what rewards come with taking such a risk (not just monetary rewards either). So, mess with their heads. Tell them about the company, but tell them you aren’t hiring. Focus on sophomores and juniors so that you can come back the next year and get their attention. Maybe they will be ready to jump.