Nor were all of the mentioned facts in the pre-trial coverage. I don't remember the stuff about the other Doig's sister, and the prison records had not yet surfaced (the prison system had been unable to find them at the time).
Which actually should never have mattered, because the trial never should have happened. Doig said, no, that is not my painting. That should have been the end of it, but the other party didn't like that and tried to get the court to say otherwise because they thought they had basically won the lottery.
This case seems odd based on the news coverage though (based on the coverage in respectable publications like The New York Times and Guardian). I would have, perhaps naively, assumed that the plaintiffs would have been expected to have at least some evidence that Doig (with a different spelling) was the artist in question before it went to trial. Which doesn't seem to have been the case.
Of course, this was a civil suit and the reality is that you can sue anyone for just about any reason. For better or worse.
If this concerns you, you should not be as dependent on items whose value hangs so tightly on the word of a disinterested (or worse, interested) party.