FWIW: The "re-establish" comes from the FED casebook (7.3.5 Situation E) [typos are mine]
With less than two outs, R1 on second and B2 at the plate, R1 attempts to steal third. In the process, B2, who bats right-handed, after swinging or not swinging at the pitch (a) makes no attempt to get out of the way of F2 throwing to third or (b) is unable to make an attempt to get out of the way of F2 throwing to third. As a result, F2 cannot make a play on the runner. Is B2 out, and must R1 return to second? RULING: B2 is not guilty of interference in (a) or (b). B2 is entitled to his position in the batter's box and is not subject to being penalized for interference unless he moves or re-establishes his position after F2 has received the pitch, which then prevents F2 from attempting to play on a runner. Failing to move so F2 can make a throw is not batter interference.
So you want to be an umpire - read the case book - it'll remind you why there are those in the stands that refuse to de-assify themselves from their lofty perch ;-)
John F,
The fact that a case discussion uses the word "re-establish" in the explanation of a situation doesn't make my comment that "There's nothing in the book about establishing or re-establishing position" wrong because:
a) My statement was literally true. I didn't purport to refer to anything but the rule book and the one little portion that was relevant to this discussion.
b) The purpose of my statement was to get the notion of "re-establishing position" out of 2017LHPScrewball's vernacular because, if you read his question, he was sort of hoping for a basketball-like use of the term that would have justified the movement and allowed him to get away with BI.
c) I did read the case, and I didn't think the casebook's use of "re-establishes" was at all helpful. In fact, it is redundant with "moves" and creates potential for confusion, such as we saw here.
In general, the precision of writing in the Fed rules is pretty poor when compared to OBR. For an example, look at how it took them two tries in 2014 and 2015 just to get follow-through interference in the book correctly.
And the quality of writing in the NFHS case book is even worse than in its rule book. I take the cases for what they are--approved rulings for the situations described. However, I feel no obligation to employ their careless wording when it doesn't help my purpose of explaining the rule to a parent fan who asked the question here precisely because he didn't want to look it up.