I've a feature to the devel branch code that prevents using any
--hostname on more than one system.
This should prevent errors with DNS management and so forth.
Previously we supported prevention of duplicate MACs and IPs, if
configured, but not hostnames.
http://git.fedorahosted.org/git/cobbler?p=cobbler;a=commitdiff;h=d9fc397b...
The release today kept me from looking at the outstanding patch queue,
so I will look at those next week and get them rolled in.
--Michael