GO!NotifyLink Enterprise Server:

A password entered in the Password Settings (Rules) such as, "aaaaaaaa" would render the same duress password.  This may prevent the duress notification from being sent, as the system cannot not distiguish the duress password from the regular password.
If users plan to enable the Duress Notification feature in the Lock Rules, the password entered in the Password Rules should not be made up of one repeating character.