Its not like a turkey on the roost or a game animal impeded by deep water.....but such decisions are up to the game regulations and the internal compass of the individual hunter. Just last night I watched a TV hunting show where a guy shot a mountain goat that was bedded.....and a long shot at that.
Several years ago I was pursuing a particular buck that I had only seen in glimpses at dusk.....just knew from rubs and such that he was pretty nice. Just prior to our firearms opener, I decided to give it one more try and snuck into a thicket along a drainage that he liked. I dug into a clump of trees with my recurve and spied a bedded deer not 75 yards from me. After watching for a time, I decided that I was going to try a sneak and see what happened. Nocking an arrow, I was ready to shoot and wired like a long tailed cat in a room full of rocking chairs at every step. If he didn't stand up, I was fully ready to shoot him lying down......but it never got that far as he was stone cold dead.....got hit by a vehicle and made it to the thicket on sheer will.