Admins should be able to add a Regrets or RSVP No button on events through the standard admin event build interface.

If a registrant clicks that button and submits their regrets they would be put in to an "Event Regrets / RSVP No" group. This could then be used as an opt-out for future event email marketing.

Please note, your competitors - iModules for example - offer this functionality.

We are aware we can create a survey and survey confirmation page, set up the survey to add respondents to a group, and then add that survey as a text link on the event details page. Its just not nearly as efficient or intuitive as having that built in to the events module.

Matt