Ok here's the results of my tests.

Test Machine 1 and 2, Test 1
O/S: Windows XP
Privilege Level: Local Admin
BREAK: Not set (default)
Console: Alwaysontop
Results: End Process on kix32.exe from Task Manager terminates the process without logging me off.
Closing the console window results in logoff.
End Task on console window from Task Manager results in logoff.

Test Machine 1 and 2, Test 2
O/S: Windows XP
Privilege Level: Local Admin
BREAK: BREAK OFF
Console: Alwaysontop
Results: End Process on kix32.exe from Task Manager terminates the process without logging me off.
Closing the console window results in logoff.
End Task on console window from Task Manager results in logoff.

Test Machine 1 and 2, Test 3
O/S: Windows XP
Privilege Level: User
BREAK: Not set (default)
Console: Alwaysontop
Results: End Process on kix32.exe from Task Manager results in "Access Denied" error message.
Closing the console window results in logoff.
End Task on console window from Task Manager results in logoff.

Test Machine 1 and 2, Test 4
O/S: Windows XP
Privilege Level: User
BREAK: BREAK OFF
Console: Alwaysontop
Results: End Process on kix32.exe from Task Manager results in "Access Denied" error message.
Closing the console window results in logoff.
End Task on console window from Task Manager results in logoff.

Test Machine 3, Test 1
O/S: Windows 2000
Privilege Level: Local Admin
BREAK: Not set (default)
Console: Alwaysontop
Results: End Process on kix32.exe from Task Manager results in "Access Denied" error message.
Closing the console window results in logoff.
End Task on console window from Task Manager results in logoff.

Test Machine 3, Test 2
O/S: Windows 2000
Privilege Level: Local Admin
BREAK: BREAK OFF
Console: Alwaysontop
Results: End Process on kix32.exe from Task Manager results in "Access Denied" error message.
Closing the console window results in logoff.
End Task on console window from Task Manager results in logoff.

Test Machine 3, Test 3
O/S: Windows 2000
Privilege Level: User
BREAK: Not Set (default)
Console: Alwaysontop
Results: End Process on kix32.exe from Task Manager results in "Access Denied" error message.
Closing the console window results in logoff.
End Task on console window from Task Manager results in logoff.

Test Machine 3, Test 4
O/S: Windows 2000
Privilege Level: User
BREAK: BREAK OFF
Console: Alwaysontop
Results: End Process on kix32.exe from Task Manager results in "Access Denied" error message.
Closing the console window results in logoff.
End Task on console window from Task Manager results in logoff.

I ran the same tests using kixforms instead of a console window. Set the console window to hide. The results were the same on ending the process. The only thing that's different is you can't do anything to terminate the script that results in it logging you off, since there's no console window to close or end task on.

So it appears the problem is only with users that have local admin privileges on Windows XP systems. If it gave an "Access Denied" when trying to end the process like it does on 2000, I'd be happy with that.