An Apple Discussions board thread harbors posts regarding problems using Fast user switching for managed clients with network home directories connected to a Mac OS X 10.3.x Server system.
It now appears that Apple technical support may be confirming the issue, based on MacFixIt reader Ray Srour's recent experience:
"Today I had the unfortunate luck of discovering a user login problem in osX server which was verified and escalated by an Apple tech support representative (xServe support). Setup as follows:
- Mac OS X server 10.3.2
- Managed client environment with user home folders on the server - root level /Users
- All clients on Mac OS X 10.3.2
- All clients use fast user switching
"Apparently clients using fast user switching whose home directory and login authentication are stored on a Mac OS X server don't properly disconnect when you log out - and even when you go to the server and select the user and manually disconnect the client doesn't recognize it's been disconnected. The only solution so far is to restart or turn off fast user switching."