Idea would be to allow some autoresponders to be set up to either trigger on event date or registration date, as determined by the admin. It would be important to allow us to measure performance of these messages.

The follow up autoresponders are useful in the immediate time period following registration, but sometimes we need to be able to message people around the time of the event. Like, the event is in 5 days, its time to do X. You cannot use the FU AR's to accomplish this because people are registering over a period of days to nearly a year before the event. The fact that the event is coming up is the critical factor.