That they lost their voice, regardless of how effective it really is in the whole scheme of things. Nothing really important happens. Voting, admittedly, is a challenge for most students, who are either not yet registered or who are registered at home. That doesn't make it right not to vote. There's no extremely rational reason to vote for president and skip local elections, which made up most of Tuesday's ballots.
Local officials affect daily life much more than presidents do.
From a political science standpoint, one vote means much more in a local election because the voter pool is smaller in the first place, and because fewer people will turn out. It's hard to avoid a presidential election, which makes it easier to remember to vote. MTV, public service announcements and even campaigns themselves plead with voters to get to the polls for presidential or gubernatorial elections. Not so for off-year elections. Sure, newspapers printed voter guides this year, but not nearly as many as last year.