First we did Hotseat.
At first all my opponents had the "default" gray Canyon car. There is no possibility for the guests to chose their preferred skin, although this would be very nice to allow this (and the painter as well for kids).
Later, one of the opponents suprisingly had suddenly my skin, so we were racing against each other with the same skin

Later in Split-Screen, only my car had the skin, and the others were all gray.

I'm not sure about your future plans for demos and free version, but for local play, it would be great if people would not have to drive with gray skins at all.