ORIGINAL: Hornfan
But I agree that harvesting by age is the best practice - it is just that you can't really have a legal standard based on age because the criteria is too subjective for enforcement.
In my view, legislating QDM is like legislating morality, and it is nearly impossible.
The problem with antler restrictions is that in the heat of the moment when you have to make a split second decision that it can be hard to judge a spread (especially if the deer is 200 yards away).
I had an aquaintance get caught this year with a buck with an eleven inch spread, and the game warden threw the book at him to the tune of several thousand dollars. He went to court and told the judge the truth and got off VERY light.
The truth was the deer was 250 yards in some brush, and he had to make a decision and shot. He got to the deer, realized his mistake, and could have easily just walked away, but he chose to still clean the deer. According to the judge, the right thing to do would have been to call the game warden and let him know what he had done, and SUPPOSEDLY, he wouldn't have gotten fined.