Facebook will soon give iPhone app users the option to check-in to events, similar to how you can check-in to places. As soon as you check-in and confirm your attendance, a news story will be published on your feed, acknowledging your presence at the event. This is an improvement since it confirms actual attendance.
The check-in icon will not be on the event page. Instead, this is available within the mobile app, users will only have the option to check-in when they are near the location and around the time the event is happening.