Setsurou's response to the suspicions cast on him.
"I got lost."
Setsurou's actual response:
"I was gathering intel. You idiots wouldn't know good intel work if it smacked you in the face with a baseball bat, so excuse me while I continue to be useful in a roundabout manner."
See, this would've worked so much more easily if people had gone along with the obfuscating stupidity angle I'd initially set up instead of bringing Setsurou to the spotlight.
As a general rule, the fact of the matter is that Soul Society's general power structure is terrible, more top-heavy than a pornstar's boob job, but no one with the know-how and no ulterior motive is in position to change it.
EDIT: Correct me if I'm mistaken, but wasn't one of the reasons that stepping before the UN was discarded as an option the simple fact that the Shinigami would be pretty much unstoppable compared to most militaries? I mean, the Quincy aside, no one is even equipped to see them, much less harm them, and any weapon a country doesn't have a counter against tends to spark arms races...