When you are sending e-mails about a poll on an Event, you should establish, WHICH event you are talking about. The poll should include as one of the first questions, wether the player even participated in that event. Otherwise, you are wasting the time of players who want to give you feedback in such polls, but cannot give input on the event. Or just send the e-mail only to people who participated. Even then, at least MENTION which event this is about. You would also assure, that you are getting feedback about the right event, and people not mixing it up with a different one.