Unregistering content hosts returns you to a page with a warning (rather than just the outcome)
1. Using the Foreman UI, select one or more hosts under Hosts->Content Hosts.
2. Select Bulk Actions->Unregister Content Hosts.
3. The hosts are removed, but the page you are returned to says:
'At least one content host needs to be selected in order to perform a bulk action.'
Rather than perhaps just confirming the outcome of the action.