Hacked voter registration systems: a recipe for election chaos

How do you disrupt the U.S. election? Hacking a voter registration database could very well do just that.
Imagine thousands or even millions of citizens' names mysteriously disappearing from a database. Then when election day comes along, they find out they aren't registered to vote.  
Some security experts warn that this scenario isn't totally far-fetched and could deny citizens from casting ballots.
"If that happens to a few voters here and a few there, it's not a big deal," said Dan Wal