My feelings on shoot flat to compensate for inadequate yardage judging skills:
There is no bow that shoots flat enough to make up for misjudged yardage. If someone is so deficient as to shoot at the same spot without regard for distance, I think they're going to miss, or worse, wound more game than they will kill cleanly. I feel if someone has that attitude they're going to take a shot without concern for distance. Is it beyond the range of their capabilities? It could well be. For some 25 yds is no big deal. Go to 35 yds and it's a different world. Small mistakes become big ones.
There is no replacement for knowing and practicing with your setup. I shoot one pin, but I know where to hold at ALL yardages from 5 to 40. I shoot fast bows, with what some consider light arrows (375 gr). But I work at judging yardage every time I shoot (almost daily). I don't feel safe in thinking I can "be in the ball park" by shooting a fast bow, without concerning myself with being "on the money" in judging yardage. There is no replacement for knowig the distance, and knowing where to hold AT THE KNOWN DISTANCE.
If you need a rangefinder, by all means use one. It's not a sin to admit you need one. It's a sin to shoot expecting your bow will make up for not knowing how far you're shot will be.
As I stated above I shoot one pin, fast bows. But I always concern myself with the yardage. That couple inch "one way or the other" can mean the difference between hitting both lungs, or just clipping one.
In a nutshell, I agree with Arthur in that shooting a fast bow to make up for not knowing the distance is wrong. Is it unethical? Just shooting the bow is not, shooting at a game animal that way is.

Phil.