I read something a while back that said you generally can't do that if it can be shown that you could remember. No idea how that works in practice though.
Correct. The attorney doing the questioning will have additional supporting evidence... documents, transcripts of prior testimony, established timelines of events, etc. So if they ask “were you at [location] on [date]?” and she replied “I don’t remember” they would simply show her evidence of her being at that location on that date to “refresh her recollection” and then she would be expected to answer. She could answer along the lines of “from this [evidence] it looks like I was” but it would be difficult if not impossible to avoid answering questions altogether.
But it forces the other party to have evidence for everything. The point of the questioning is to gain additional evidence from the answers. But if all answers are "If that's what it says, then that's what it says" as Richard Sackler https://youtu.be/-qCKR6wy94U?t=952 then it's apparently the effective way to go
Right, it definitely makes it more difficult but keep in mind that you don’t need to gain additional information in order to gather additional evidence.
For example, if I have a piece of paper - Exhibit A, that demonstrates you were at a certain place at a certain time, that’s definitely valuable evidence but at trial opposing counsel could call into question the source of the document, chain of custody, or a number of other issues to contest its accuracy and/or validity. But if I have you on the stand and show you that piece of paper and you say, on the record, that it does seem like you were there, now I have Exhibit B - a record of your testimony, at the very least admitting the document seems legitimate and reliable. But most jurors would take your statement as pretty close to an admission.
Exhibit B is highly valuable because it’s almost impossible for your lawyer to contest.
As entertainingly frustrating as Sackler’s deposition was his responses were indeed some of the least valuable he could have possibly provided. I’m sure that was part of his legal team’s preparation for the meeting. “If that’s what it says then that’s what it says” is a meaningless tautology. But keeping up that sort of response throughout an entire line of questioning is difficult even in a deposition and takes a certain amount of IDGAF attitude that Sackler clearly has in spades. A deposition is also a bit different from the grand jury testimony Chelsea Manning would have given because a deposition isn’t a courtroom proceeding. Responses like Sackler’s wouldn’t fly if he were in front of a Judge.