Does supervised device mode prevent restore on another computer in recovery mode?
I think the answer to this question is No, supervised mode does not prevent restoring on another computer when put into Recovery Mode.

When tested, in recovery mode, it acted like the device wasn't supervised at all.  It proceeded with restoring back to defaults as if it was nothing.

BUT, a strange thing happened when the iPad was plugged back into the original machine that put it into supervised mode - the iPad went back into recovery mode. I opened up Apple Configurator and it started a "refresh" process.  This seems to be the same thing as preparing a device, as it restored it back to what it was like after putting it into supervised mode in the first place.  During this refresh process, it re-installed iOS 7.1.1 and re-applied the profile that was setup initially with Apple Configurator.

Tested with an iPad 2
Apple Configurator 1.5 (424)
Mac OS X 10.9.2