The people icon and number sitting just below the image on the Event Page represents the full number of guests going to that event. The Contacts Going section of the Event Page is a list of people you know from your contacts that are going.
TO HELP ENSURE PRIVACY – only the host of an event can see ‘everyone’ that’s going. Guests can only see people from their contacts who are going. This is designed to stop unwanted people snooping around our social lives. If you want to know who’s going to an event – GO TO THE EVENT and see them in person!