Background:
A simple case of yet another 'move X spaces' wording that should probably be 'gain X MP' instead.
Question:
Q. Does the Feat Hustle give 3MP or allow the hero to move 3 spaces?
A1: Hustle should read "Play at the start of your turn. You hero gain 3 extra Movement Points this turn." Note that this change, from "allowing to move X spaces" to "gain X movement points" also applies to all other similar wordings (eg Tahlia)
A2: Hustle gives a hero the ability to move 3 extra spaces during their turn. These spaces do not cost movement points to enter, and you can choose a mud space, for example, as one of these space without paying any extra MP.
A3: Hustle gives a hero the ability to move 3 extra spaces during their turn. These spaces do not cost movement points to enter, but must be 'empty'. You cannot, for example, enter a tree space with one of these spaces of movement.