But for all we know intelligence services could be using LLMs for years now, since they are usually a few years ahead of everybody else in many regards :-)
I'm sure language models and transformer techniques will be (or more likely: already are) an important part of the contemporary systems that do this stuff. But I'm skeptical that they care much about GPT-4 itself (or other general models).
I'm not skeptical about whether they think it is useful and an important capability to incorporate ML techniques into their systems, I'm unsure how much utility they see in general (the "G" in AGI) models.
How? I'm not trying to be combative, I genuinely am curious if you have an idea how these things could be usefully applied to that problem. In my experience working in the information security space, approximate techniques (neural nets, etc.) haven't gotten much traction. Deterministic detection rules are how we approach the problem of finding the needle in the hay pile. So if you have a concrete idea here that could represent an advancement in this field.
In a world where false negatives--i.e. failing to detect a sharp needle--are the worst possible failure mode, approximations need to be handled with exceeding care.
For instance, neither of your examples - surveillance or automated drones - has anything to do with AGI. They don't need LLMs to do mass digital surveillance; they already do that and were doing it for decades before LLMs were a twinkle in anyone's eye. Sure, they'll try to tap into the user data generated by chatgpt etc. (and likely succeed), but that's not a different capability than what they're already doing. And automating drones - which, by the way, this is not future technology as you seem to imply, it's here today - is a special purpose ML system, that maybe benefits from incorporating an LLM somewhere, but certainly isn't pinging the chatgpt api!
But sure, you're exactly right at the end, I have no idea whether they see other angles on this that are new and promising. That's why I asked the question, I'm very curious whether there are any real indications thus far that militaries think the big public LLM models will be useful enough to them that they'll want to put a thumb on the scale to favor the companies running them over the companies that make their bucks on copyrighted content.