Which rule???
 

Runner on 1st. The batter pops up, and it looks like it's going to drop right into the 3rd base coach's box. The coach refuses to budge, and the third baseman bumps into him and misses the catch. What's the call?

7-6-I or 8-7-O? Runner ... or batter ... is out?

My opinion only...

I would rule per 7-6-I and have the batter out since that would have been the most likely result if no interference had occurred. With no interference, it's extremely unlikely that the runner on first would be tagging up and trying to advance on this particular play.

My opinion and belief after reading both rules is that 8-7-O is to targeted more on toward a fair batted ball and/or a ball in play that is being thrown in an attempt to play on a runner.

Again, just my opinion.....

When a coach purposefully fails to vacate a portion of the field (including the coach's box) needed by the defense to execute a play on the batter, the batter is out.

FWIW ISF 8-9-r-2 says runner closest to home is out when a coach interferes with the defensive team's opportunity to make a play on R or B-R

Actually, the more appropriate rule is ISF 8-2-k, which covers interference by anybody on the offensive team (minus the batter, a runner, the batter-runner, or the on-deck batter) on a foul fly ball. Under that rule, the runner closest to home is ruled out unless there are no runners; in that case, the batter is ruled out.

But that begs a separate question: "Why the on-deck batter in the exception?" For the other exceptions--the batter, batter-runner, and runner--the player interfering is ruled out. But if an on-deck batter interferes, who gets ruled out? It seems to me that the on-deck batter shouldn't be included in the exceptions.

I have the batter out due to interference by the coach in the 3rd base coaching box.