They do indeed, to a certain extent.
There was numerous example of hopeless divebombs at T2 that resulted in the overtaken driver being hit, pushed out and overtaken without an apology. I know it's tricky to brake consistently at the right moment, but if you do this the best thing to do is to lift off to give the position back, or at the very least a verbal apology.
Second race 1st T2 was abit of a mangle i think we went in 4 a breast so there was plenty of swapping paint. I lost abit of time but nothing mega and the guys were faster than me anyways. Aslong as your not smashed of or spun its all good but yes a quick "sorry man" doesn't take to much effort.