I am sure it is possible and that im overlooking the solution but during conforming when adding an action to the segment the proportional link for scaling is most of the time disabled. Sometimes it is on though but it does not save it or anything.
I have not found the solution in the preferences.
There is a setting for creating your own action default. Set up an action the way you would like it to appear whenever you are starting a new comp, then navigate to Action>Node Prefs>Objects & Maps>Default Setup and poke the Set Current as Default button. From here on in, whenever you add a new action it will be set to the default you desire.