I just saw a documentary on these shooting ranches and I don't think they should exist at all. The offenders will mistreat the animals to the fullest extent and get away with it.
Most of the animals are drugged and/or tame and make for a "pretend hunt" for the people that frequent them.
I would prefer a Senators' ranch instead. In other words, how would you like to be one of these helpless animals who have nowhere to hide from people shooting at them?