If you require batch mode (password-less) login and want ssh to fail quickly without it, use these two options from the client side (see http://linux.die.net/man/5/ssh_config for descriptions of these):
$ ssh -o BatchMode=yes -o IdentitiesOnly=yes thehostname
Or you can add it to a an ssh/config entry for .
Host thehostname
IdentitiesOnly yes
BatchMode yes