No one has access to PM's.
The only way PM's could be accessed would be if the Admin, and there are very few of them, would change the password on the account and then log in.
The person would know if this happened because they would no longer be able to log in.
The Admin would not be able to change the password back to the orginal because they are encrypted and no one, not even an Administrator, knows or can retrieve your password. If you forgot your password all that can be done is assign a new one.
BTW: PM's seem to be working fine.