I'd love for that to be user surveyed, because I will guarantee you that most people have no idea that this is happening. They just know the bubble color is different and nothing else. Especially since iMessage the default "text messaging" app. Which everyone associates with SMS. People with technical knowledge even have no idea why Android messages sometimes never go to their iMessage app on iPad/Mac...which happens to me constantly with people missing important messages because something breaks in between the two.