Originally Posted by beernutz
One reason I always raise the finger even on 'obvious' out calls is that many calls which appear obvious to the caller are not so to the other team or player. I think at least once a match when playing doubles there will be a high lob that hits 6 feet or more beyond the baseline and no call will be made, then someone on the other team will ask if it was in or out because their view was blocked.
But if a ball hits the fence on the fly several feet up, it's hard to have your view blocked. Probably some of your opponents in these situations have felt like "raising a finger" in return, even if they haven't.