Outlook 2002
User A access other users' calendars by File/Open/Other User's Folder.
The other users set up access permissions for User A in Calendar Properties
Persmissions
I can't think of any reason why you'd get a delay in that scenario. What Outlook has to do is locate the other mailbox, check your permissions on the Calendar folder, then display the data.
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Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003
and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers