It seems that if user1 is running a wine app and user2 is running a wine app, and user2 wants to perform a wineboot command, wineboot will wait till user1 closes out all wine applications.
My observations are based on running winetools as user2 to install software while user1 continues to run a wine application. When it comes time to perform a "Windows Reboot", winetools just hangs there waiting for the wine processes to terminate.
I think that wineboot should be modified to only attempt to stop processes owned by the user calling wineboot.
-Joe Baker