@Riddler I won't insist on Crocus' bounty since I have no way to check on that, but I distinctly remember that one marine when Koby enlisted (right after being provoked by Luffy to chase him out of town or whatever) saying something along the lines of "don't underestimate us, we know you were a pirate but we're turning a blind eye on that since you proved your worth with the Morgan situation and all". I remember it because being so early in the story it gave me some indication on how to perceive the marine as a reality in this world. Maybe it was a fan translation, it was quite a while ago.
Anyway, there's a lot of good counterpoint that can be made to prove that "it's not so easy as you make it sound", but that doesn't really shift from the main point: there's clearly a big rift between:
This 8 year old girl may possibly be able to read an ancient language, based on the fact she lived on the same island as some other people who could, which means that in the case she manages to go around the world visiting all the islands where these ancient stones are located (something that's been done only once in almost a thousand years) may actually discover something about this old story ---> relentlessly hunt her down l, no matter how carefully she hides, and attempt to kill her at the first chance
And
These guys actually went there, learned ALL the story and came back ---> jeez there are a lot of small inconveniences in tracking them down, let's hope they keep the secret...
So, maybe there's a "the moment something even slightly suspicious happens to one of us the beans are immediately spilled" kind of deal
Or maybe it's Shanks using whatever leverage he has on the Government
But I feel like what happened not only to Ace himself recently but to every possible child of Roger right after his death shouls have counted as an infringement on the WG part...
So right now I'd say I'd be glad if it's actually explained somehow, but I'm not really holding my breath for it.