Do not provide Continue option on Encryption warning dialog boxes

This setting controls whether Outlook users are allowed to send e-mail messages after they see an encryption warning. If you enable this policy setting, encryption warning dialog boxes do not contain a Continue button, which means that users must cancel the sending operation entirely. If you disable or do not configure this policy setting, if Outlook users see an encryption-related dialog box when attempting to send a message, they can choose to dismiss the warning and send the message anyway.