For our event registrations, we often send out an email to all attendees that contains an itinerary and allows them to schedule specific seminars or sessions within the events. For this reason, it would be extremely helpful if we could require the registrant to fill out email addresses for all of their attendees.
The ability to email users that have registered for an event, would also be useful in case the date or location has been changed. If there was a button, or feature right on the specific even form it would save school quite a lot of work.