I had a similiar situation as Popsracer. I would pass this certain racer, he would come charging up after me and take me out in the next turn. He did this couple of times. The next time I passed him and he came up after, I went wide, slowed down and let him pass. He took him self out in the next turn. He caught on after a few times.
Most of the racers who do hack are usually beginners, they don't hack intentionally and the ones who hack purposely can't stand to loose.
Sometimes if a racer hacks too much, intentionally or not, gets a warning from the race annoucer here.