When you're creating your Event Invitations and chosen your Selection(s) of people, you are able to choose your Exclusions, however, once chosen, we never see them again which prevents us from troubleshooting our users.  These need to appear someplace.  (similar to previous idea where we need to be able to see the names of the selections used in creating each invitation).  By the way - I'm reporting this as 4.0 which we are upgrading to this weekend, and although we're currently on 3.0, I've checked these in 4.0 as well and they're not there either.