This is actually something we practice to an extent for our club races at our track. There are 2 or 3 of us "fast" guys at the track who normally win. So we generally start the races in the back, and depending on what kind of day we're having we may start up to a half lap back.
In many ways this helps us out quite a bit, since we have to do a lot of passing, while still fighting for our position with the other fast guys that start with us. Meanwhile the guys up front get some "1st place" time which with experience calms them down and improves their driving. Also, it gets the newer guys some excitement when they see us on their tail waiting for a passing opportunity. It's funny how many times new drivers crash right after the RD says "Bobby is in 1st place!" Once they get used to hearing their name it becomes easier for them.
Now for big events, it's all out. But something that we've noticed since starting this practice. We've had fewer first turn pileups.
Paul