How does the single Boon effect of the Trick Shot card works?

It says that the target cannot use reactions to this attack... reactions different to active defenses I suppose (since active defenses are declare before the roll).

There are actions that have reaction trait which allow acting on someone else's turn, other than active defences. Don't have cards to hand so can't cite examples.

"Shrug it off" is an exemple of Reaction trait action card. It increases your Soak value by 2 for the attack that just hit you.