Conditions that affect all checks (as frightened) also affect AC.

[Dante Doom]

This has been confirmed in today "In Pale Mountain Shadows" by Mark.

This is a good boost to intimidate as you can stack frightened+flat-footed for a boost in accuracy!

It will come in an errata eventually.

Just posting so you guys know too.

[Pramxnim]

YES, AHA! Mark mentioned that Frightened used to apply to checks and DC, which includes AC, so I'm glad they're officially acknowledging that now.

Flat-Footed and Frightened are gonna be the basic blocks of combat now, letting PCs adjust their accuracy on the fly by debuffing enemies.

[CommanderCoyler]

Sounds interesting: Spend the first action of your turn to shout at someone to make your two attacks be against 1 less AC instead of whiffing a -10 attack :p

[Xenocrat]

Sick and enervated become even worse, too.

[Jason S]

Good to know. I don't really think of AC as a "check".