21) CAR LIVERY
21.1 The provisions of the Code relating to national colours shall not apply to the Championship.
Both cars entered by a competitor must be presented in substantially the same livery at each Event, any change to this livery during a Championship season may only be made with the agreement of the Formula One Commission. In order that the cars of each team may be easily distinguished from one another whilst they are on the track, the on board cameras located above the principle roll structure of the first car must be predominantly fluorescent red, and the second car fluorescent yellow.
I believe David's car was illegal? Unless some sort of exception was made... BAR tried to enter two cars one season with different liveries but were told it was illegal, so they simply combined the two liveries and drew a zip down the middle...