Hypothesis testing and the law
In the Court of Pprune, if something is more probable than not, or 50.01% for those with a maths preference, then that could be regarded as more than a rumour, and quite possibly a fact.
In Civil Courts, that is the same evidential standard of proof - whether in the UK, US, South Africa or Australia.
Criminal Courts generally require a standard of evidential proof that is beyond reasonable doubt, again well north of 75% for the maths minded.
No one here is asserting any hypothesis for criminal behaviour on behalf of the crew. Most of us know the chilling effect that this would have on air safety. Better a safety culture than a blame culture.
So, a potential partial hypothesis is that the crew commanded idle from the engines......