Call or noncall? You make it ...

The "non-call" in the final seconds created a huge controversy in the Lakers' 93-91 win over San Antonio Tuesday, and you hear high school coaches talk about calls made or not made in the final minutes all the time, especially in football.
Unless it's flagrant, should game officials whistle a rule infraction in the final minutes/seconds, or should they swallow their whistle and let the game take its own course?
Make the call, or non-call, that is the question.
Is their responsibility (in high school games) to officiate the entire 48 minutes (football) or 32 minutes (basketball), or is it acceptable/important to ignore an infraction/incidental contact that has/has not the potential to change the outcome in the final moments so long as neither player gained an advantage?