If you send a calendar invite through PoliteMail and have unchecked the options in Outlook to restrict users from requesting responses, allowing new time proposal or allow them to forward, these setting do not hold; users can request responses, allow new time proposal and forward the invite. This seems like a bug but after speaking with PoliteMail support it is operating as it was designed therefore I am submitting it as a new idea.
Thank you for your idea. We will share it with the Development Team.