Thats easier to do than you might think usually it's because your not familiar with the flagman.
I did it one year at Volusia County Speedway during Dirt Speedweeks ( yep we ran dirt and asphalt back in the 70's-80's ) during one of the preliminary races I had a straightaway lead came around and the Flagman showed two flags rolled up meaning two to go. Next time around he was waving the White and my spotter said "You got it Won" all I heard was You Won! So I lifted and moved to the bottom of the track to pick up some weight. Finished 4th butt still in a transfer spot after I realized what I'd done and got going again......Dad did'nt talk to me the rest of the night lil Irishman was PISSED!
Another time it worked out better for me My good friend Chip had been kicking our butts at Ocala Speedway all summer long. During a special 50 lapper that paid Big Bucks for the time he lead from the pole to the white flag with me a half straight back. He took the white flag and lifted going into 1 & 2. I thought he'd broke or ran out of gas and passed him on the backstraight, I could'nt figure out why he was waving at me?
At Ocala they used to have the top 3 cars stop in the front infeild for pics and stuff, while I was standing there with my 1st place trophy he walked over slapped me on the back and told me what he'd done and that I was buying Beer that night. Racing was Fun back then.