Q: In a Closed Economy, can a Regent Lord tax a Vassal City under Imperial control? What about an Outlaw Lord?
A: A Regent Lord is bound by Truce law when taxing a Regent Vassal city under imperial control, and bound by Closed Economy when taxing an Outlaw Vassal city under imperial control. An Outlaw Lord can always tax Vassal cities regardless of Empire control.
https://cards.ledergames.com/card/ARCS-F326A