Oh, it's very true, and the NASCAR drivers use it as a regular tool. In oval track racing, they run close together. But passing may be difficult, because most of the time, the low line is the one that is desired, and the slower car is running on it. So the driver behind attempts to place his vehicle on the outside or inside rear quarter panel. In that position, the air to the spoiler of the leading car has it deflected, with a reduced downforce. The rear end loses traction, and if the driver is lucky, his car just drifts up to the higher line while the car behind just motors by. Sometimes the lead car winds up out of control, spinning out.
In NASCAR, running that close, and even bumping each other is regular, and considered acceptable. Personally, I believe any bumping or unfair treatment is unacceptable. maybe that's why I am never going to consider myself a NASCAR fan.
As far as cheating, the history of racing is one long, continuing saga. I am probably aware of hundreds of occasions. Heck, I used to do it myself, when I was a mechanic for a pro level ice racer. The rules allowed only stock sheet metal screws on the knobbies for the ice. But we used to grind the edges to a sharp bevel, then send all the screws out for heat treatment. Lots of work, and a wee bit of money, but we had good traction.
Or how about the NASCAR crew chief, after inspection he used to run his fingers along the radiator fins, pushing them in, and reducing drag.
