[Gandalf Parker]

Its also been used by something as simple as a Scout with the Soul Contract. The invading army is able to move on and continue taking provinces because that one scout is able to hold the castle BETTER than the large army could against ANY force of ANY size that is inside the castle.

This was extensively discussed in IRC. There is no way to get a turn for buying PD or setting Patrols. Move and Patrol would seem to be an answer, but thejeff is correct that its apparently not an option when you dont own the province.

Making "Move and Patrol" work would be one answer. A better one IMHO would be to have "Break Siege" be automatically followed by "Patrol". It seems logical to me that if I have left the castle to break a siege that I would then be outside the castle, not back inside it defending.