[AtlUmpSteve]

I find the RS a bit wordy, and it may imply a contradiction, but it isn't. With runners on 1st and 2nd, if a ground ball assist goes to 2nd as the initial play, isn't the force off for R2 headed to 3rd (or to even return to 2nd)? Not different for a subsequent appeal.

I don't have a current casebook, but I remember an ASA case play, where the B/BR/R was thrown out at 2nd stretching a single on a throw to another base, and that removed a force play on a prior runner missing a base (changed it to timing for successful appeal).

Added: At best, the language is meant to reinforce that BR not reaching 1st is not, in itself, a force out, so both situations (BR and a trail runner) would remove a force play on a prior/advance runner.