We have a lot of meeting room calendars that were set up long ago in a older verison of Exchange. These meeting rooms were setup with the default permission of Author which lets staff book directly into the calendar. With Exchange 2010 the meeting room attendant functionaly arrived which allowed us enforce polices like rejecting reoccuring meetings with no end date from being booked. This works great except that with the author permission remaining on meeting rooms users can go into the room calendar and book the appointment direclty avoiding these policies.
So the easy solution would be to just blanket change the default users permission to meeting rooms to a read-only role like reviewer or limiteddetails. But this then stops users with existing meetings booked directly into the calendar from editing there meetings. So I would like stop new meetings being bookable directly into calendars, but exisiting meetings can be edited or removed by the owner of the meeting.
I thought I could get this resolved by changing the calendar permissions to:
ReadItems, EditOwnedItems, DeleteOwnedItems, FolderVisible
This stops me from creating new items but trying to cancel or change the meeting results in a permissions error. Why?