Can you prevent a player from scoring battlefields by using Gust (or other reaction damage) in response to a hold trigger?

Ruling: No, you cannot use Gust or any reaction damage to prevent scoring from holding a battlefield. There is no 'hold trigger' when scoring from holding a battlefield at the beginning of the turn - the scoring happens without a trigger that can be responded to.

Nuances:

• This applies to any reaction that would kill the unit, not just Gust
• By the time any reaction could occur, the player would have already scored