The main problem are the run-off areas. This has basically encouraged to push other drivers off and it is all viewed as okayish. If it was gravel, I'd say it is definitely NOT all right to leave other driver NO room at all and push him into the gravel. Remember, what Schumacher did to Frentzen in Canada in 1998, or many other instances. Back then it was a clear rule both cars must have room to stay within the white lines. But nowadays it has become vague due to excess amount of run-off area.