I' m planning on shooting instinctively with my compound bow this summer. I don' t think its unethical at all as long as you practice before hand. I have a friend who use to shoot his old Browning compound with no sights, a cheap plastic flipper rest, and shooting fingers and he was able to hit a grapefruit at 30 yards.
Oh by the way, I' m shooting a compound instintively for bowfishing carp and gar...