In 2016 ONCJ 155, the judge says with regards to a witness:
 In an effort to explain to the Court her continued socializing with Mr. Ghomeshi following the alleged choking incident and over the rest of the 2003 Canada Day weekend, Ms. DeCoutere testified that she wanted to “normalize” the situation and “flatten the negative”, and to not make him feel like a bad host. So, she stuck with their plans and she continued to see him over the weekend. She testified that she kept her distance and certainly did not do anything intimate with him. Having firmly committed herself to this position, she was then confronted with a photograph of herself cuddling affectionately in the park with Mr. Ghomeshi the very next day.
The judge then uses this, among other arguments, to support the position that the witness is not trustworthy, which ultimately causes the case to fail:
 Let me emphasize strongly, it is the suppression of evidence and the deceptions maintained under oath that drive my concerns with the reliability of this witness, not necessarily her undetermined motivations for doing so. It is difficult to have trust in a witness who engages in the selective withholding relevant information.
But I'm thinking: evidence can't be presented mid-trial, the Crown counsel must have already been aware that the defense has this photograph. They could have talked to the witness beforehand and could have told her that this photograph exists and therefore that lying about it would certainly fail. If they did so, then perhaps the witness wouldn't commit herself to the position if she knew defense had evidence against it, and would thus appear more trustworthy.
There are several similar paragraphs in the file for other witnesses: the defense asks the witness, notes the answer, then presents evidence contradicting the answer and concludes that the witness is deceptive.
Why wouldn't the Crown tell the witnesses beforehand that defense has all this evidence so that the witnesses wouldn't fall into this 'trap'?