Originally Posted by thejuice
From someone's perspective standing in the ad service box, I could place a ball a centimeter off the far side line on the deuce side and the ball would look "in" to the net player. Your partner, in most cases, would be covering that deuce side and would therefore have a much better view of the side line that you would. That centimeter could potentially cost you a match because of what you thought you saw versus what actually was. 99% out is still in.
I think the more common problem in tennis (in your example) is when the net player calls the ball out, but the partner on the deuce side line is seeing it as in.
I have to say, I do not appreciate it when my partner at net tries to call the baseline or far side line. I'm there. I'm watching. I can see. Just let me call it.
Now, if you see me running full speed and stretched out and off balance, yes, go ahead and make a call if you see it clearly. Just make sure it was clearly, clearly out. And if you didn't get a good view of it, and I couldn't be sure either, it was good. I can live with that.