mmm... trade lines able to welcome any sort of traveler through their system, its not entirely incorrect if the trade lane rings depend on a passive hyper-space field that keeps resonating continuously over and over again, when a ship approaches and activates its own hyper-space field both ring and ship fields combine launching the ship through the rings. Think of a bubble of air forming underwater, the only way it can go is "up" the deeper the bubble forms the smaller it is but as it approaches surface it grows bigger as pressure is minor.
The armed guns mounted on the rings are another matter, they do have IFF sensors and optical recognition systems, if possible the guns should be stronger to attack any hostile ship to it IFF affiliation, preventing rogues and pirates from using the lanes.
