Ha! yup, heard that a looong time ago, but not from any racer. Having qualified for racing licenses and won championships in several types of racing including road racing, it's actually more complicated than that; you're looking at what direction the wheels are pointing, which wheels are on/off the pavement/grass and what'll hook-up or break-loose in the next seconds... e.g., if someone in front of you is two wheels off on the left side, and starts to turn back onto the track, he'll probably loop straight across the track in front of you and pound the right-side wall or sail across the right-side glass. I have pics of me absolutely threshold braking for exactly that situation, which looks like "huh?" in the first pic, then the next pic, I would have absolutely t-boned the guy if I hadn't braked so hard (and no, driving to where he was, half in the grass, wasn't an option).

So, if you don't have any clues, and have a half second to make your choice, I suppose it's better than no rule of thumb, but I wouldn't rely on it as a primary technique.