It is not illegal to drive or own a black and tan. It is just illegal to have one painted that color scheme.
http://www.leg.state.fl.us/statutes/...n%2003#0321.03
321.03 Imitations prohibited; penalty.--It shall be unlawful for any person or persons in the state
to color or cause to be colored any motor vehicle or motorcycle the same or similar color as the color or colors so prescribed for the Florida Highway Patrol. Any person violating any of the provisions of this section or s. 321.02 with respect to uniforms, emblems, motor vehicles and motorcycles shall be guilty of a misdemeanor of the first degree, punishable as provided in s. 775.082 or s. 775.083. The Department of Highway Safety and Motor Vehicles shall employ such clerical help and mechanics as may be necessary for the economical and efficient operation of such department.