During Depositions, a Lawyer Cannot Tell His Client How to Answer
From Max Kennerly’s “Be A Potted Plant: Sanctions For Deposition Coaching and Witness Conferences”:
The defending attorney is indeed a “potted plant” with only two exceptions: they can raise objections in a concise, nonargumentative and nonsuggestive manner, and they can instruct a deponent not to answer a question when necessary to preserve a privilege or enforce a court order.
No attorney would, in the middle of their client’s cross-examination at trial, loudly clear their throat and say “if you know” or “don’t speculate” before the client answers. You don’t have to be a lawyer to see that as little more than an attempt to coach the witness into claiming they don’t know something that they actually do know.