One major thing to consider is angles. I am a football and basketball official and I like to use the examples I learned when I was training to officiate in times like this. 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. Officials have blown many games because of them trying to overrule a partner when they were out of position. The credibility of the officials are gone and the integrity of the game and match are in jeopardy. The best thing to do is just swallow your whistle (an official's term), or in other words, just be quiet.
(2) Wilson ProStaff 95S with leather grips
(2) Wilson BLX PS90