Does Hustle Affect Moves that Bypass Accuracy

Aerial Ace and other 'always hit' moves are considered as not having an accuracy modifier, and are therefore unaffected by changes to accuracy or evasion from any sources, including Hustle. This means that Hustle will boost their power only: accuracy for these moves will be unaffected.

Note that 'always hit' moves are denoted in-game as 'Accuracy: --':

If a move has 'Accuracy: 100%', then it will be affected by the Accuracy changes from Hustle. Pound for example:

All physical moves gain the 50% bonus, including moves that always hit. Since they always hit, a 20% decrease in accuracy will have no effect.