To the extent one’s client (“C”) is to  testify at a deposition, s/he needs some suggestions, lessons, instructions, training, etc.–the level depending on the nature of C. There are lots of things to emphasize. Here’s one.

L: “Suppose, my dear C, that you are ask a question like this one: ‘Do you you agree me with me that p?’ What should you say? How should you answer?”

C: “Shouldn’t I say “yes,” if I think p is true, or no, if I think its not?” I wonder if this is true.

The real question should be one of two possibilities: (1)  whether p is true or not, or (2) whether C believes or does not believe p.  Whether C agrees with opposing counsel is irrelevant.  Moreover, it is probably not knowable by C, since he does not have access to the mental states of opposing counsel.

Perhaps C should consider answering the question “I don’t know.”  The trouble with this correct answer to the irrelevant question is that it’s a subtle matter, and someone might be confused about the meaning of “I don’t know” uttered in this situation.

Another approach is for C to say, “I don’t understand that particular question.” The depositioner will then ask, “What do you not understand?” The witnessing C might then say, “I can’t tell whether you are actually asking me something about the correspondence of our mental states as to p or whether you’re asking me about what I believe with respect to p.”

The depositioner will back away immediately and as the relevant question cleanly. This is true even is s/he scowls contemptuously or laughs sneering.

I like the approach even though looks over-technical. First, it keeps the record correct. Second, it lets the depositioner know that C will not be pushed around or subtly dominated. It makes C more in control.  After all, the deposition of of C, so it’s his/her deposition, and not at all  the deposition of the depositioner.