dont know about all other states but this is straight from the 2008 Fl statutes 320.01 (26)


commercial motor vehicle means any which is not owned or operated by a governmental entity,which uses special fuel or motor fuel on the public highways,a GVW of 26001 lbs or more,or has three or more axels regardles is used in combination when the weight of such combination exceeds 26001 lbs .
A VEHICLE THAT OCCASIONALLY TRANSPORTS PERSONAL PROPERTY TO AND FROM A CLOSED MOTORSPORT FACILITY AS DEFINED IN S549.09(1)(a) IS NOT A COMMERCIAL VEHICLE IF THE USE IS NOT FOR PROFIT AND NO CORPORATE SPONSORSHIP IS NOT INVOLVED.

so by reading that I would assume in Fl as long as you have no sponsor and do not make a profit and you stay under 26000 lbs you are not a commercial vehicle.

so I wont lose any sleep over this.