When I do an e-mail blast through Marketing Event e-mails in NXT, the system should be tracking who among my constituents e-mailed has registered. Then, when I do a second blast and a third (being the squeaky wheel : -), the system should know/see who has already Registered for the event and blocks them from getting subsequent solicitations. This way the second and third etc. solicitation e-mail blasts aren't annoying those folks who have already registered.

Other RSVP platforms I've used have this feature built in, and its super helpful to me, and courteous to the constituent.