Run validation on automatically added hosts
I have a couple hosts that automatically get duplicates added (because the FQDN doesn't match what Foreman thinks it is, this is an entirely separate issue). What I've noticed is that the automatically added hosts don't validate that they are unique. For example, the automatically added hosts have the same mac/ip as the real host. Foreman notices this if I go back and try to edit the real host.
Validation of parameters should probably be performed for any hosts that get automatically added.