[greymule]

I haven't done FED in several years, but as I recall there was no ambiguity about BOO. This from the 2006 BRD might help:

Play 65-83: R1, 0 out. Able should bat but Baker steps in and hits into a 6-4-3 double play. The umpire recognizes the appeal of the defense. Ruling: In FED, R1 remains out. Able is out, and Baker bats with the bases empty. In NCAA and OBR, R1 returns to 1B, Able is out, and Baker is the next batter.

Note 94: FED has had a tough time with BOO since they added the unannounced editorial change ("outs made on play stand") in 1991. For three glorious years the ruling in play 65-83 above would have been a triple play. Improper batter Baker hits into a double play. So: (1) the improper batter is out, (2) the runner on base is out, and (3) the proper batter is out. In 1994 they killed that possibility with: "An out for BOO supersedes an out by the improper batter on a play." (7-1-2b Ex)