I appreciate all that you say. I acknowledge that a dishonest player will have an edge under legal moves, at least until he gains a reputation for “accidental” plays that favor himself. I am not trying to say that there are no negatives with legal moves.
Of course, to gain any benefit, a dishonest opponent will have to have some “cooperation” from me. Malintent notwithstanding, he can gain no advantage, either by not noticing one of my misplays or by making a misplay of his own, unless I simultaneously err. It is a very small number of plays we are talking about.
The reason am I willing to accept these negatives is because they are outweighed by the positives. The overwhelming majority of players are not dishonest. Going by the numbers bandied about in a recent thread here on cheating, we can expect to encounter 25-50 honest players for every dishonest one we meet. Stated another way, 25 to 50 times we will benefit from legal moves for every 1 time we do not.
In addition to the many that benefits of legal moves that you enumerated, there is one other—a very large one—that you did not. I am speaking about civility and sportsmanship.
When you consider the very bad feelings created by the tactics Herb Gurland used to win a match recently, you will see what I am talking about. All of those feelings would have been avoided by legal moves. I do not know whether any long-term relationships were damaged in that episode, but the potential certainly existed.
Backgammon is a very small community. The weekend tournaments are long and grueling. The last thing we need is to create lasting enmities by embracing absurd rule interpretations that are both hard-nosed and cold-shouldered.
I, for one, do not want to win my match, and then eat dinner alone.