Currently, and not very intuitively, you can't get ScriptData from the normal method. You can, however, get Spark.getData().scriptData.whatever
It's there -- so may as well let us get it the intuitive way via Spark.GetData()
If the SD is truly somewhere else behind-the-scenes, just detect if it's a request and redirect that data to us.
It's a little thing, but it's more than just convenience -- it's for new people, too. This was another thing that I wish I knew long ago. I must have spent hours trying to figure out why my sd wasn't showing up in a req. The answer was making a ticket and having you guys tell me :P