Heartland Cacher: Archiving since the event is long over and everyone has had time to log his/her attendance. If not, the listing is not locked, which also goes if the CO wants to add some additional remarks. This also prevents it from appearing on pocket queries unnecessarily. and keeps it from continuing to appear on cacher's search lists. From the guidelines link text
After an event has occurred, the listing is to be archived by the geocache owner.
Thanks
Heartland Cacher