Yeah, but aren't all the senior nobles in the city going to be curious when Lord Shojo goes to jail for reasons that can't actually be explained? I mean, fine- if the 'magistrates' that Hinjo are referring to are really whatsisface and whozit the lawyer guys doubling as senior azurite legal officials, maybe they can actually secure a conviction without raising awkward questions, but somehow I doubt it.
I would ordinarily incline to agree, but I seem to recall(?) there's a panel in HTPGHS where Hinjo remarks with surprise that the SG really turn out to exist (because, for some unknown reason, Gin-Jun has to yell the name of the organisation out loud while he's conducting clandestine raiding operations in foreign territories.)