They're the sponsor logos on the car artwork and so are functionally meaningless - though I have heard that the physical promos for these sponsored cars come with a 4 hazard limit dashboard, rather than a 3.
Hum, I should do the math and see from there if I can guess how much 4 warnings loc would change the feeling of the game.
It would of course increase the number of flat-outs so that it probably wouldn't really reduce the number of locs.
But would that be better for the game ?