There are many reasons, not all of them serious, why an administrator might suspect that an account is being misused. For example, someone may have inadvertently created two Athens accounts for themselves, or there may be suspected abuse of a resource or of someone else's account. In this case, the apparent user of the account(s) should be notified, and the account suspended while the matter is investigated.
The easiest way of suspending an Athens account is to reset the expiry date to a date in the past. This will prevent the account being used while it is under investigation, and if the account is reinstated the expiry date can be reset again.