Actually, Shiny, you are dead right: floating grounds (bad, intermittent) are a nightmare. The battery ground is absolutely critical. As long as it connects to the bike's frame, bare metal, no paint, with a
tight connection, you are golden. Be sure to either torque to spec (70 lb-ft is good), or use a lock washer (nylon lock nuts will not make as good of an electrical connection, so a metal lock washer is a safer bet). Cheers!
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII