Fix the real issue, and ban taking more than 2 seconds to replace your ball after marking it, starting from the time the ball reaches 6" above the green. I don't care about someone using the cheater line, so long as they are quick about it!
But if you ban the cheater line itself, you would need to ban anything that can substitute as a cheater line. Someone with sharp eyesight or a lot of patience might be able to use the numeral "1", the letter "i", or the letter "l" to aim, so maybe you should only let people use Precepts numbered 2 thru 9.
Under no circumstances, no matter how badly someone is playing and has run out of balls and doesn't want to buy more, allow anyone to play with range balls. Those have the most prominent cheater line of any ball ever made!
