10.04 (a) The official scorer shall credit the batter with a run batted in for every run that scores (1) unaided by an error and as part of a play begun by the batter’s safe hit (including the batter’s home run), sacrifice bunt, sacrifice fly, infield out or fielder’s choice, unless Rule 10.04( applies; ( The official scorer shall not credit a run batted in (1) when the batter grounds into a force double play or a reverse-force double play; or (2) when a fielder is charged with an error because the fielder muffs a throw at first base that would have completed a force double play. But this is really referring to an error that allows a runner to advance, not one that prevents it. 7.06 When obstruction occurs, the umpire shall call or signal “Obstruction.” (a) If a play is being made on the obstructed runner, or if the batter-runner is obstructed before he touches first base, the ball is dead and all runners shall advance, without liability to be put out, to the bases they would have reached, in the umpire’s judgment, if there had been no obstruction. The obstructed runner shall be awarded at least one base beyond the base he had last legally touched before the obstruction. Any preceding runners, forced to advance by the award of bases as the penalty for obstruction, shall advance without liability to be put out. I think this is key. The rule says he has to be awarded at least one base, which means scoring regardless of if he would've actually made it. So say the runner is 3 steps past third and decides to return to the base because the catcher has the ball. If the third baseman obstructs his return, he'd be awarded home and the run would score but logically he wasn't actually driven in.