Vista - Using mapped drive as 'Documents' Folder location

I have observed something and wish to pass it on to hopefully save someone
else a little time if they have the same thing occur. The shortcut to the
'Documents' folder disappeared from the profile for one of my users and try
and I might I couldn't find the 'Documents' folder again to look and changed
where it pointed. I finally realized what happened is that the folder was
pointing to a mapped drive - in this case 'Z' which pointed to the users home
folder on the server. When this mapped connection was lost so was the
documents folder. For clarification, I am not saying they couldn't open the
folder, it was gone from the browse and default tabs from all applications
and was not a choice when I opened the user from Start, username.

Remapping the drive made the 'Documents' folder reappear and function
normally.