I think there is a happy path though and she stuffed it up by not responding for a request for information while she went overseas as they were investigating the matter. When she returned they put her in detention as they deemed her a flight risk. I don't know what information they asked, but it would seem prudent to provide it or say you don't have it or you are overseas and cannot get it at the moment, rather than simply ignore it.
reasonable suspicion is a pretty well established concept. importing controlled substances would get an arrest warrant easily anywhere if law enforcement decides to pursue the case.
the administive pretrial detention is also pretty common, especially nowadays with the ICE craze.
nobody should be treated like this, agreed, but that doesn't mean that the process has no correlation to the level of guilt established and the certainty of it.
(the real problem is that it's way too many bullshit laws.)
Japan has a very harsh system, this serves as both a deterrent and also incentivizes people to make their equivalent of plea deals.
There's nothing magical about a criminal trial, especially in Japan, since there's not even a jury. And in general there's no magical threshold for proving guilt.
Nobody should be treated like this. We agree.
I'm trying to point out that unfortunately is a trade off, it works, and unfortunately a lot of people are getting treated like this all over the world for things that are administratively easy to prove and are illegal by the letter of the law, so technically easy to "prove guilt".