alt Hacker Newsgeneric emails sure, but harder to conjure up a convincing picture of a specific book club, where it is, who will be there.
If people are taking the time to generate this kind of AI invite, then it must be a very high value event. Possible, but I suspect there are more mundane reasons for avoiding the admin
There are plenty of examples of AI being successfully used to emulated the email / messaging style of a specific individual already known to the target, for spear fishing attacks, and fake video and audio of family members tricking people. I think you're substantially underestimating the peak ability of AI these days