Explanation/Reference:
Explanation:
In normal lockdown mode the DCUI service is not stopped. If the connection to the vCenter Server is lost and access through the vSphere Web Client is no longer available, privileged accounts can log in to the ESXi host's Direct Console Interface and exit lockdown mode. Only these accounts can access the Direct Console User Interface:
Accounts in the Exception User list for lockdown mode who have administrative privileges on the host.

The Exception Users list is meant for service accounts that perform very specific tasks. Adding ESXi administrators to this list defeats the purpose of lockdown mode.
Users defined in the DCUI.Access advanced option for the host. This option is for emergency access to

the Direct Console Interface in case the connection to vCenter Server is lost. These users do not require administrative privileges on the host.
Reference:
https://kb.vmware.com/selfservice/microsites/search.do?
language=en_US&cmd=displayKC&externalId=1008077