Within Events it would be helpful to have a defined 'Host' for the event (each of Contact, Co-ordinator and Speaker could be used, depending on the circumstance, but each could also be inappropriate for certain scenarios). This would be an additional field on the Event itself, maybe on the same tab as the Speaker tab. Note that the concept of 'Host' does already exist in events, for the lead booker of several registrations (i.e. the person who brings the guests), but there doesn't exist a concept for the Host of an event as a whole - except where this person is simultaneously the Contact, Co-ordinator and/or Speaker.