unless the person whose folder that is being opened has granted rights to the person trying to open it they should not be able to. By default, Even if that person is an exchange admin.
This is called am implicit deny. The only way a user could access another user’s mail or other exchange folders is if they delegated control to the other user or an exchange admin gave the access to the second user.
not by default if the person is an exchange admin. I have those rights on our server and can access any and all user’s inboxes etc, without them granting me access to the folders.