Is there a reliable way to disable fast user switching (programmatically or via profiles) in macOS 10.13 and 10.14?
Here is the command:defaults write /Library/Preferences/.GlobalPreferences MultipleSessionEnabled -bool 'NO'
You can also create a profile to disable it, and with a profile they will not be able to bypass the setting. It is under LoginWindow -> Options
Thank you very much, @mlizbeth and @tomhastings!
I found this however doesn't stop concurrent user login (fast user switching) through remote access (screen sharing, ARD or VNC). It only removes the switch user on the lock screen.