I don't think there is any problem with accuracy. I also have yet to see this decision that comes to mm, at worst case is a matter of a few inches. With matches being recorded at 50 frames per second, it means that they can take the image when the ball was released. Within 1 frame (0.02 seconds) the players cannot move much to make any difference, so the stoppage of the match should be very accurate. After all that is simply a problem of camera calibration which is more or less solved. Then all it remains is to draw the lines which any competent person can do, and here we get extremely accurate decisions. Probably not 100% accurate, but very accurate, much better than what the refs can do in real-time.
In addition, the majority of calls are not in these extreme situations of inches, so the accuracy in the vast majority of decisions should be 100%, with a few marginal ones, still being extremely accurate if not perfect.