Answered: Are Negation Barrel required to be introduced?

At a recent Vex Competition, I thought I heard the ref give directions that the Negator barrel MUST be introduced to the Iso Zone start tile at End-30sec mark.

<SG7> bullet 2 in Gateway rules full 080311.pdf, emphasis added:

This seems clear enough to me, but I’ll ask here to clarify:

Example: Alliance robots are busy at far end of field, so they decide to NOT do matchload of Negation barrel to prevent opponent from picking it up to score against them.

Question: Is Alliance allowed to NOT introduce Negation barrel ?

Alliances are NOT required to introduce the Negation Barrel (or the Doubler Barrel or Match Loads). The rule you quoted with the emphasized text spells this out.