Your opinion (and not merely what the rules say): should the cheater line be legal or not? Why?
I wondered when you'd chime in.
Yes, I do think it should be legal.
As long as the ball can be lifted, it would be impossible to have a rule where it would have to be replaced in exactly the same orientation as it was before. Then I have to study the orientation before I lift the ball to make sure it gets back in the same orientation. If there was mud or something on the ball so I couldn’t see the orientation when I lifted it, I’d have a hard time getting it back the same way. If the ball has any marking on it, whether put there by the player or the manufacturer, it is too fine a line to enforce any rule as to positioning.
Say the rule said you couldn't put the ball down where the line pointed along the line of play. A player could put it down with the line at 90 degrees to the line of play so that he lined up his clubface to the line instead. What about a ball with a + sign on it or the "V" that is printed on Calloway's ball or the V that I put on my ball directly below the number to identify it. I don’t need a line when I have a pointer. Neither of the two lines in the V point down my line. Tell me I can’t have the point pointing there and I can put it the other way around so that the open end points there. Still works.
And, of course, all ball markers would have to round and blank.
So, the only way to enforce such a rule would be to say that there can be no markings whatsoever on the ball or that it can never be lifted, neither of which are practicable (as the rules like to say).
If the issue is one of pace of play, that should be enforced, not this. If it is somehow giving a player an advantage in putting the ball, he still has to read the putt correctly and hit it correctly.