See the logging of Event Caches section of the listing guidelines   Any Event Cache (including Mega, Giga and CITO Events) can be logged online if the geocacher has attended the event. Event Cache owners can request that cachers sign a logbook, but this is optional and cannot be a requirement for logging an Event Cache.   Generally this is interpreted to mean, PHYSICALLY attended the event. (When you read the requirements for Mega and Giga events, that "attended" means physically attended, i