It's passing through to the `AWS::EC2::Instance` class from the AWS SDK; so it will have a value if the machine has a public DNS name.

This could potentially have problems, as people have previous expected a "magic" fallthrough to other methods that will return values. Perhaps the default value for `contact_point` should do the "magic" fallthrough unless the Capistrano variable `ec2_contact_point` is set. Does that sound reasonable @christianblunden @rjocoleman?