@KamiKira00 I haven't read the novel so i don't know if it will go like this but:
if he actually goes deep to the point of directly attacking the flagship (which if they aren't complete idiots will NOT be near the frontline) like hell the military will be able to properly follow his actions among literally hundreds of ships bigger than his.
Even if they suspect that he actually used an illegal object it would be hard to prove HE was the one to activate it.
And if i am in possession of something powerful but illegal and i am a freaking mercenary (which means a LOT of contacts with authorities and/or border patrols) i'd try to get use AND rid of it as fast as possible.