That's like saying that "you" need to write down the information of every car you see. They're not security or law enforcement. So, they don't "have to" scan a lone ship that visits the star system.
You are assuming that a "scan" is like "writing down" the information. If ever we have the technology to remotely acquire information on objects (especially in space) it will be utilized the same as "simply looking at" a car today.
If we ever get the technology to have independently owned space craft that can travel between solar systems, they will be capable of moving at speeds and vectors and at distances that would make getting ANY identifiable information impossible. You would have to use computer tracked scanning technology. The sole exception is if everyone irrevocably radio (or equivalent long distances technology) transmits satisfactory identifying information
constantly (like every time one transmission ends, within a few minutes
at most, another one begins).
Why? Because ships would be appearing and disappearing
at random within the solar system constantly. The
only way to identify (or even re-identify, in the case you leave visual and/or sensor range) would be the scanning or reading of (what you can only hope is) a reliable transmission of identification.
These are
not motor vehicles traveling on predefined paths (called roads), not even airplanes traveling on (mostly) predetermined flight paths. These are interstellar space craft that can travel 360 by 360 by 360 at any orientation at varying speeds between anywhere
under the speed of light and
over it.
To assume that "security" or "law enforcement" would be able to be present in any way beyond general long distance "full system" scans, and then reactionary travel to the location of emergency is like assuming that anyone driving on Earth will be caught by law enforcement immediately, regardless of where they are or whether a law enforcement vehicle is currently within immediate visual range of them. In other words, impossible, impractical and insane.
No. In an environment where individuals can own and operate
interstellar ships (heck, even in an environment where different
nations or plane and simple different interest groups can own and operate interstellar ships) it would most likely be
required to scan and identify nearby ships, if only so they can automatically be reported to a central intelligence authority.
In these situations, if you were to rely on the "good will" of those around you or the immediate response of local authorities, you would be dead. Unless you had immediately accessable escape pods with shielding and/or armor better than the ship that was just attacked (or crashed into)... and, let's be honest, if you did then why wouldn't you use that shielding/armor for the ship? ... then ANY emergency that permanently disabled your ship would kill you. You can't "pull over and wait by the 'side of the road' in space"...
The only point I will concede is that they don't have to scan "in detail" every ship. A brief "identifying" scan would be enough, and it would only need to be done by those who are along the vector of the ship originally. I.e. not "every ship in the area coming to do a full structural scan." However,
even then if my understanding of the very premise of the manga: that he Isekai-ed into a universe with the equipment he had in a game, but that (most importantly) IS
NOT THE UNIVERSE OF THE GAME, then he literally has a ship that is unique to this universe. He is in a solar system that is known for manufacturing and design of ships with something
unique. Of course he is going to be harassed with scans trying to understand (and probably rip off) the unknown designs of his ship.
And, if I don't understand the very premise of the manga, everything written before "The only point I concede..." still stands.