I think anyone who claims that is fooling themselves
Hey Chin,
I look at it this way, if your drift is same every shot, then you are not really drifting as it is the same every time.
But if one shot you drift zero the next you drift a few boards to the Right, then the next a few to the left. Well you have a problem.
But if you do the same thing every shot, who cares it's zero because you end up where you intended to be.
So the drift should be measured over a number of shots, not just one shot. Because you may just get it right on target the one time you checked.
So, one shot is zero the next might be one left the next one right. So throughout a game I may have had a drift of 2 boards best to worst. Nobody can expect to be perfect, the same way as I rarely hit my target more than once or twice in a row, it is always a board here or a board there. Walking with a ball swinging from one arm is always going to make a difference to where you finish, it is not a natural action. If your timing is bad, well there is no way you will walk straight.
This is what makes us human and why it is called human error. I will not even start on the topic of what we think we see and what is really happening.