Obstruction, Look Back--NFHS

[Tru_in_Blu]

"Is a pitch a play" seems to have been discussed before. I think NCAA folks claim that pitching or catching is considered a "play".

NFHS definition of play:
ART 2 Make a Play
a. Any action by the pitcher intended to cause a reaction from the runner(s) as it pertains to the look-back rule. (Some are arguing that the OBS voids this as a play.)
b. Any action by a fielder who is attempting to catch or gain control of a batted or thrown ball.
c. An attempt by a defensive player to retire a runner or a batter-runner. (Maybe this semi-applies, but if the defense does manage to tag the runner off a base, that will kill the play and the runner will be placed accordingly.)

In the Umpires' Manual, page 35, bottom of the page.
Obstruction: The base umpire should immediately:
1. Give the.....
2. When the play becomes dead, make the proper OBS award.

So, if'n we have no "plays", what makes the play dead besides the runner being tagged off a base or an umpire calling "time"?