I think it is important to remember that umpire should make a fault call only if he is absolutely sure there is a fault. We don't know if it was in line of sight of the umpire / service judge and it could be that it did not look as clear from the chair as in the photo. We can feel really smart looking at perfect angle and close ups on the tv screen but that is not how you see it in reality. Surely you cannot give the line judge to make these calls because it should be consistent. It would also be a bit like if at the court would let the guard at the door to decide if the suspect is guilty??... Very few line judges are qualified umpires and often there could be someone who barely knows the game. Saying in or out is the best some of them can do and biggest reason for IRS as they often do it poorly. You can't hope that line judges can call faults precise and consistent. Anyways, most of the time umpire and service judge should be able to pick these. Anyways, it's not a kind of fault that would give any advantage. Are you sure we should get frustrated over these being missed?