Sometimes you get to the point that you have to do something. Just watching a big, mature buck trot out of sight, without the chance for a shot can be very frustrating and disappointing.
In cases like that I will try to stop the deer by making a loud sound. Not yelling or whistling but a soung that ends in Wyatt Earp's last name......(sounds kinda strange, I know but it sometimes works
). I simple 'ERP' may do the trick. In most cases this sound will not frighten any deer. They may simply ignore it or hopefully stop long enough for a decent shot.