I have a bundle that I want to distribute, only if a user is not logged in. It doesn't appear that I can use requirements for this.

I have found that this command will return an errorlevel=1 if no users are logged in:
reg.exe query hku /s /k /f "Volatile Environment"
(kinda cool, eh?!)

So, I have this command (Launch Executable action) as my first Install action, and specified Success Return Codes=1, thus, an errorlevel of 1 should continue with the subsequent actions of the bundle. However, if the command returns errorlevel 0, it should be considered a failure, and not continue with the bundle actions. This is not happening. What am I missing?