When I first started watching baseball, I very quickly understood on an intuitive level what a “ground rule double” was.  But it’s rule 5.05(a)(5)-(9) that actually explains what a ground rule double is, to wit:
5.05(a)(5) …A fair fly ball that passes out of the playing field at a point less than 250 feet from home base shall entitle the batter to advance to second base only;

5.05(a)(6) A fair ball, after touching the ground, bounds into the stands, or passes through, over or under a fence, or through or under a scoreboard, or through or under shrubbery, or vines on the fence, in which case the batter and the runners shall be entitled to advance two bases;

5.05(a)(7) Any fair ball which, either before or after touching the ground, passes through or under a fence, or through or under a scoreboard, or through any opening in the fence or scoreboard, or through or under shrubbery, or vines on the fence, or which sticks in a fence or scoreboard, in which case the batter and the runners shall be entitled to two bases;

5.05(a)(8) Any bounding fair ball is deflected by the fielder into the stands, or over or under a fence on fair or foul territory, in which case the batter and all runners shall be entitled to advance two bases;

5.05(a)(9) Any fair fly ball is deflected by the fielder into the stands, or over the fence into foul territory, in which case the batter shall be entitled to advance to second base; but if deflected into the stands or over the fence in fair territory, the batter shall be entitled to a home run. However, should such a fair fly be deflected at a point less than 250 feet from home plate, the batter shall be entitled to two bases only.

That’s a lot of words to basically explain that if the ball goes out other than as a fly ball or a foul ball, the batter gets two bases.  Big whoop.

But I didn’t pick this rule just to say “oooh, baseball is more complicated than it looks!” I picked it because there’s something hinky going on in these rules and I don’t get it.  Take a look at the bold language in each of those rules and then riddle me this, Batman:

1.  Why are the runners mentioned in subparts 6,7, and 8, but not in 5 and 9?  If the batter gets two bases, the other runners must advance, too, right?(1)
2.  What’s the difference between the batter being entitled “to advance to second base only”(subpart 5) and “entitled to two bases only” (subpart 9)?
3.  Why the difference between “runners” (subparts 6 and 7) and “all runners” (subpart 8)? 4.  What’s the distinction between “entitled to two bases” (subpart 7) and “entitled to advance two bases” (subpart 8)?

I suspect that this is my law degree showing.  See, in law, there’s a rule of legal drafting: don’t use different words to denote the same thing.  In plain English, say the same thing the same way every time.  If you don’t, as any lawyer can tell you, you run the risk of your opponent or your judge parsing out the language to figure out why there’s a difference in language.

As a lawyer, there’s a difference between “runners” and “all runners” and between “two bases” and “second base.”  I suspect, though, that I might be over-analyzing the baseball rules, which weren’t written by lawyers(2) and aren’t meant to be interpreted so strictly. Either way, though, I’m going to be asking this question at umpire school. I’m sure they are going to love me and not think I’m annoying AT ALL.

Do you think they have a fantasy camp for baseball rule writing? Because I have some suggestions.
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1. Unless the runner is on third, of course.
2. As far as I can tell. Google is remarkably thin on the identities of the Playing Rules Committee.