There have been studies around for decades that show that when ordinary people are given absolute over other people's lives, without accountability or clear standards, a substantial number of them become debased and cruel. I think of famous studies in which students were hired to be jailers for other student subjects in California: a culture of abuse emerged quickly. Social psychology has documented this territory.
Also, without credible witnesses and trustworthy documentation, no one can set a limit to scandal. If abuse happened in one U.S. detention facility, no one can establish that it didn't happen in all of them. Any photo of sadistic behavior is now unanswerable evidence of sadistic behavior -- and such photos are can be mass produced.
When someone says, "Let's do this in secret, without witnesses, so that no one will ask embarrassing questions," the right answer is, "If you do this in secret, without witnesses, and anything at all goes wrong, the embarrassing questions will never end, and you will have nothing credible to say in response to them."
We need more inspectors, more auditors, more cameras, more preservation of chains of evidence, more light -- everywhere public. This is basic. It is more basic than: what we do. However stupid or misguided or even criminal a project may be, its flaws can be exposed and its damage can be contained, if we as a culture just have a strong preference for light over darkness.