How is a crapcan race unlike a typical track day?
That’s how. On a track day, you take the “racing line” at all times. Do that in a race with a bunch of red-mist-plagued yahoos and you’re going to get skewered. An open lane is an open invitation. You have to expect that the person behind the person behind you is going to shoot the gap, skid through the braking zone, and trash the unlucky person on the racing line. Make sure that’s not you. Check your mirrors before the turn, and if you don’t trust all the people behind you (and most of the time you won’t) shut down the inside lane by driving in it. No, you won’t go as fast, but you’ll discourage apex-stealers, and if you do get hit, it’s better to absorb that impact on the bumper than the wheel.