The default /etc/ntp.conf specifies a key file and key
IDs for all three sorts of keys; the default key file
contains default/sample keys. The net effect is that a
NTP server started without commenting out this section
of the ntp.conf file will allow anyone on the Internet
who knows the default /etc/ntp/keys contents -- ie most
everyone who can read an RPM file somehow -- to perform
remote control of the NTP daemon. This allows anyone on
the Internet to control the local clock (delete all the
configured peers, add a set of peers under your control
that feeds the target system bogus time), among other
things.

 I strongly urge RedHat not to ship an /etc/ntp.conf
with keys enabled. With the requestkey, controlkey,
and trustedkey statements commented out, the daemon
will not allow this remote control. (I would suggest
commenting out the line that specifies a key file too.)
I'd also suggest a strong comment in both files that one
should NOT use the default values, so people aren't
tempted to just uncomment things and run that way.