So then any lawyer, in order to avoid a deposition, would just have to claim that they intend to sue someone and they would be immune from deposition. They don't need a pending case, just the threat of one.
Yes. I just finished reading O'Mara's Motion for Reconsideration, and it appears to lay out that test as well (paragraph 19 of the motion). However, the privilege is not absolute, and the privilege can be waived.
O'Mara's argument has several parts. First, that Crump is not opposing counsel. But, if Judge Nelson persists in finding that Crump -is- opposing counsel, he has waived privilege as to the facts surrounding his interaction with Witness 8 and subsequent production of evidence to various law enforcement agencies. And even if neither of those is found, by Judge Nelson, O'Mara describes how the evidence defense seeks is not protected, using the legal standard cited by Nelson (the Fireman's Fund, Shelton, and Boughten v. Cotter cases), in her March 4th Order.
One place that Nelson's logic breaks down is where she assumes that defense wants to depose Crump to learn about facts surrounding the shooting itself. But defense is not seeking that from Crump. It is seeking to learn the circumstances surrounding the appearance of Witness 8.