I was just reading the Apple Thunderbolt Wiki and stumbled upon this:
25) If I eject a Thunderbolt device using the Taskbar tool or disconnect the Thunderbolt cable, can I reconnect it again without restarting?
No. A directly-connected Thunderbolt device that is removed with the Taskbar tool or by disconnecting the Thunderbolt cable will not be recognized until you restart the computer.
Is that really true? Does that mean I would have to restart my macbook, if I was connected in the morning, unplugged it, put it to sleep, then went to the office and wanted to work on afterwards?