I hope we made it clear in the first few pages of chapter one that the ITT is a government body. But what are their responsibilities? Well, sure, as you’ve seen, they like to harass pilots by writing citations, but their mandate is more profound than monitoring traffic. Interstellar Trade and Transit is a federal department of the GRotG responsible for the safety and security of non-military spacecraft as well as the hyperspace trajectories they travel, but, as I said in the previous update about FTL, ITT is also responsible for regulating the production, distribution, and use of fuel bricks.
Fuel bricks are produced at “refineries” located within certain star systems where local topology permits the efficient production / retrieval of material native to hyperspace. While the refineries are often privately-owned, this is usually only in the strictest technical sense, because laws governing fuel production mandate exclusive ITT control of all activities related to fuel bricks. This means that refineries may contain, at a maximum, a token cadre of bureaucrats representing the real owners.
While some governments express dissatisfaction with this arrangement, claiming monopoly, the majority in the GRotG are of the opinion that the amount of energy stored by fuel bricks necessitates their careful handling and / or monitoring by a trusted central authority, to prevent criminal or terrorist misuse of the substance that makes interstellar travel feasible.