Version:            (using KDE KDE 3.3.2)
Installed from:    Debian testing/unstable Packages
OS:                Linux

A (remote) calendarfile should be reloaded before inserting/saving any new events (i.e. Mozilla Sunbird does this). If not, you can lose data (events). 

Imagine the following scenario:

Computer A loads (remote) calendar file.
Computer B loads (remote) calendar file.
Computer A adds an event "X" and saves the file.
Computer B adds an event "Y" and saves the file.

Event "X" is lost, because Computer B doesn't checked out the calendar before adding an event and uploading it. B overwrites the calendar file computer A uploaded. 

You can minimize the chance of loosing data if you set the load calendar intervall to a few minutes but it would be easier if korganizer just check out the calendar before writing to the same location.