Document rules visible

If you check Show/Hide Rulers in Preferences the last document will determine if rulers are shown or not.

If this setting is on and your open document has rulers visible, your next document (or the next document you open) will show them too.

Users do. You can set them by document by going to View>Rulers>Show Rulers.

You can also change them from artboard to global rulers (one ruler for all artboards) in the same menu.

EDIT: I see you tagged SDK on your question. I think what you would need is a script checking that the ruler is on or off depending on what state you want it to default to.