Actually I do.
Yes there can be only one commander at any one time. However I suspect the more senior might find themselves culpable if they did not assume control when faced with a breach of the law.
The disgnated PI is responsible.
Expereinced passengers are not.
I have flown with ATPL's that could not solo a Cessna 172. Experience on type is can be more valid than total flying experience.
I think those trying to blame the non designated P1 miss the point.