I have seen on numerous occasions that organisations name their admin account anything but admin or administrator. Most often of course people in help desk would use their own account with different levels of admin rights for day to day tasks, but sometimes help desk staff would use a shared admin account that wasn't named admin or administrator, and I was wondering if that's for reasons of safety and security (e.g. harder to guess that the admin account is laracroft).
In Active Directory accountnames must be Unique and AFAIK the account named "Administrator" is one of the defaults that is created and best practice is that "use of the Administrator account should be reserved only for initial build activities, and possibly, disaster-recovery scenarios.".
The means that other admin accounts, the ones people actually use, must be created with a different login name.
It's merely for security and traceability reasons for why we should use a nominative account instead of generique one, because it's hard to guess in case of a brute force attack ,and in case if anything happend we now who did what and when.
PS: It not at all a good pratice to share an administrator account between multiple users ,which will create traceability issue .