Does Assault apply when a unit moves into an unoccupied battlefield?

Ruling: Assault does not increase a unit's might when moving into an unoccupied battlefield because moving into an unoccupied battlefield begins a non-combat showdown, and units only gain attacker or defender designation during combat.

Sequence:

• Moving a unit into an unoccupied battlefield begins a non-combat showdown
• Without combat, units don't have attacker or defender designation
• Assault is a passive ability that is only "on" (active) when the unit is an attacker
• Since the unit isn't an attacker in a non-combat showdown, Assault doesn't increase the unit's might

Nuances:

• The unit still has Assault as an ability, but it doesn't provide the might bonus
• Assault is a passive ability, not a triggered ability, so it's either "on" or "off" and cannot be responded to
• If a unit with Assault moves to an occupied battlefield (creating a combat), then Assault becomes active and provides the might bonus