Issue Accepting and Rejecting Meetings from Your iOS Device
This is a heads up for admins facing an issue where calendar invites on all meeting attendees everyone’s calendar gets deleted when an iOS 6 user declines a meeting from his device.
More information regarding this can be found in the thread: https://discussions.apple.com/thread/4368289?start=0&tstart=0
So basically when a user decline’s a meeting with his iPhone or iPad running iOS6, the action delete’s it from all meeting attendee’s calendars.
For now, it is recommended to send a notification to all users in the company asking them not to accept, reject, move, edit meeting requests from your iOS mobile device.