Sometimes I am fast enough on a reboot of the remote PC that I can quickly switch back over to my main, but sometimes there is no time. But if I miss that opportunity then SOL. So if you were controlling the remote PC at the point in time the connection is lost then you're stuck without controls for either PC. Multiplicity needs to be able to detect the connection loss event and switch back to the local PC.
To be clear in my terminology, if not already obvious:
Local/Main PC: The PC with keyboard and mouse attached used for control.
Remote PC: The remote PC being controlled.
In very rare occasions it seems to work properly and switch back to main.