Does Open Showdown activate Assault (e.g., if you start a showdown at a location with Chemtec, does he get his Assault 2)?

Ruling: Open Showdown does not activate Assault if the battlefield is not controlled by an enemy player, because you do not gain the Attacker designation.

Nuances:

• If an enemy unit joins that battlefield during the Showdown, it will stage Combat which ensues after the current Showdown ends
• In that subsequent Combat, you will be the attacker (and gain Assault) since you applied Contested to the battlefield