In my current marathon game, I currently have robots and robo-ports, but not yet a personal roboport.
By accident I ran into the following case: One of my stations had the wrong wiring for balanced unloading. The chests and inserters were already in place. I updated the wires (and condition) for one inserter, made a blueprint and placed it over the other inserters as well.
I expected some robots to come and connect them up. But it turned out the wires were placed instantly, without robots. The wires were not even taken from my inventory, but appeared out of thin air.
After searching the forum, I found this post. But I think this case is different enough to start a new thread, because there are no robots involved.
[0.15.21] Free green/red wires with blueprint and no robots
Re: [0.15.21] Free green/red wires with blueprint and no robots
This is probably not worth fixing, it would add nothing to the game to force you to decontruct and reconstruct the whole setup just to setup the wires correctly