alanback: there's nothing to be gained by hitting.

Sure there is. Fun!

Your one goal is to get past his back men, and hitting makes that harder, not easier.

Is that true, though? It's not just getting past his back men, it's getting all his men off before the opponent does. Failing to hit gives 19 pips to the opponent. How many rolls would that save the opponent in equalising and getting ahead? That must be weighed against the extra chances of 4 men and a one-point table detaining the blot sufficient to win.

Actually, one possible continuation after not hitting is that the opponent rolls 2-4 and moves 12/10*/6 to make the 6-point. But even if it's a non-hitting 6, that's the 6-point made. Thus, after not hitting, 17 rolls will give an immediate two-point home table. That's four times the chances of dancing, and the splendid 6-6 off the bar is lost.

there's nothing to be gained by hitting.

Sure there is. Wins!