The idea that they would "fix" a race is completely absurd. Too many car owners have too much money tied up in their operations to go along with it. The drivers wouldn't go with the notion that "it's __________ turn to win this week". Not to mention that I doubt Nascar, and their independent contractors (owners, drivers and crews) would be able to hide a conspiracy that large. Having said that, the timing of caution flags when certain drivers are about to go a lap down or are in the "lucky dog" position opens them up for scrutiny and potential criticism of their practices. I haven't watched a Nascar race in years and don't miss it one bit.