As sysgate I believe many servers to not allow direct log in as root or even comms.

Where I currently work we have to log in under our own user name then su or ssh to the relevant user. The reason behind this is (as I'm aware) to log who has logged in as comms\root and what changes they have made.

So if something was to go wrong the sysadmins can find out who made the change and ask them why