FT frames this as some aggressive escalation tactic, but document retention letters are extremely standard practice. At this point they're basically a formality, as any former Apple employee at OpenAI really ought to know by now that they could get dragged into this. Hold letters can be aggressive if you send them before you've even filed a complaint, but if anything, Apple is late to the party with these.
I'm not a lawyer, but I would also guess they need to "flip" these folks against OpenAI and get them to cooperate in the lawsuit against the actual folks with big pockets. I think they're essentially alleging a conspiracy by OpenAI and they need as many examples as possible to make the case that this was a pattern and standard practice, not just one or two idiots acting on their own.
So if I'm a former Apple employee and I get one of these scary letters, I'm asking my attorney if I could get out of a lawsuit by sharing any information I have about any potential OpenAI shady practices.
They’re not late to the IPO party, which was postponed by OpenAI, It may turn out that that was a mistake. OpenAI probably should’ve gone ahead, particularly in light of the pending court case.
I routinely send them in whiplash and slip fall cases re surveillance video, phone records, etc.
Something similar happened to me when I left Microsoft for Apple (I moved from the Visual Studio team to the Xcode team). MS spent six months trying to prove I'd taken "industry secrets" with me. I hadn't. The entire thing felt like a personal attack and was extremely stressful.
It sounds like, in this case, Apple has hard proof that documents were stolen.