Winesses who finally realize that their 15 minutes is over routinely disappear, on their own volition, from public view. The other side has nothing to do with it. I'm sure that is what MM meant and that was my meaning in an earlier post, as well. After witnesses get exposed to evidence that contradicts them, their factual certainty sometimes wanes to the point that they are not even called to the stand. I think that will happen in this case.
The defense has the power to subpeona witnesses and to compel testimony. The defense can also introduce earlier statements made by the witness. All; that needs to be done is to read the initial statements and then go over the number of times LE questioned and re-questioned that witness.
Did LE point out inconsistencies in the witness' statement or conflicts with other "know facts".
Do this enough times with enough witnesses and the jury starts to think that LE is pushing its own agenda.