NFHS v USA Softball rule difference

[teebob21]

These cites look good. USA Softball does indeed consistently use the upper edge of the collapsible fence as the dead-ball boundary. I like your mnemonic.

Players in all codes can jump, climb, and hang on a fence to make a play, but if it falls over flat, the location of live-ball territory might change. In NFHS and NCAA play, once the temporary fence goes flat, the dead-ball line is established to be where the plane of the originally upright fence would intersect the plane of the playing field, or in other words, the bottom of the fence.