Docking rings are a concept of the "space elevator" to guide ships through the upper atmosphere onto the planet surface. Most ships would be unable to survive entry without the use of one, as proved by ships exploding if they enter the atmosphere of a planet without a docking ring. And since space elevators are a bunch of machinery, they can be controlled by the local government. That doesn't mean that in RP factions cant send packages and people onto a hostile planet in drop pods or spy ships, its just a whole lot harder for them.
