Key in on what he just wrote..."a few races"...
If you run them for too long before flipping, the wear on the tires due to the camber of your setup and just plain running around in a circle may make a change to the car's handling when you flip them. The greater the wear, the greater the change. So either flip them often, or if you measure the tread depth before you run them, you can monitor the wear and make the change based on the wear you see.
People pay a lot of money to have camber and profile cut into their tires before ever using them. It improves the dynamic (as you race) relationship between the tire and the track. Generally, for LTO race tracks, negative camber is cut into the RS and positive camber in the LS and all profiles are generally cut flat so more tread is on the track. More camber is cut into the front tires than the rear. Flipping a cut tire will not work, nor will rotating them. So if you run uncut tires on dirt for too long, the wear pattern can become a big factor. Just monitor the wear and mount the tires to take advantage of the wear. For instance, say you notice a good amount of wear on the inside of your RR (positive camber worn in). Flip it and run it on the RF(flipped positive camber tire is now negative camber) or switch it to the LF.