A Fall from Grace?

You are the only judge in a Modern Masters 2015 Sealed PPTQ.

Angus is playing against Neil. Angus swings with his Battlegrace Angel, saying “exalted” as he taps it, and Neil says, “No blocks.” Angus takes his pen and says, “So you take 5 damage.” He writes this down and continues, “and I gain 5 life.” Neil disagrees because Angus didn’t announce the lifelink trigger from the Angel when he attacked, and calls you.

What do you do?

Judges, feel free to discuss this scenario on Judge Apps!

AnswerAs Charles noted, there is no infraction in this scenario. Both triggered abilities from Battlegrace Angel are triggered abilities that affect the game state in non-visible ways. So Angus must demonstrate awareness of the abilities the first time the change has an effect on visible game state. That moment is when Battlegrace Angel deals combat damage.
We should explain to Neil that Angus has not missed any of those triggers and why, then ask them to continue playing.[/answer]