That's not what I mean. You assume that the TV camera is perfectly aligned with the finish line, because that's how you determine the position of the advertisement relative to the line. However, if the TV camera is offset from the finish line, depending on height/focal length/orientation and aberrations of the camera, the line would appear offset relative to the advertisement. Therefore you determine the wrong position of the line compared to the advertisement. That would always be the same for the full video of the race, so watching the race will not change this.