Brian Gaynor (briang(a)pmccorp.com) said:
As I recall this was added to fix a problem when using LDAP
authentication. Without it if the LDAP server was unreachable even local
logins (i.e. root) were disabled. If you're not using LDAP it is safe to
comment out. There was also talk of adding a "quiet" option to this pam
module, not sure of the status though.
The pam module has a 'quiet' option; authconfig does not set
it by default (yet).
Bill