Scout couriers, by virtue of their various missions (mail and courier duty, expoloration, charting, search and rescue, and detached duty) are constantly *moving*. The scout you see today might just be the same one you saw three months ago way back up the main. Then again, it might just be a different one. Add to the fact that there are so darned many of them, and that they all look the same... and you have a very commonly seen ship.