>I don’t think it is what the original commenter meant, because they were talking about catching cheaters.

That's why I mentioned it. Worrying about training on the submitted paper is not the first thing I'd think of either.

When I've reviewed papers recently (cancer biology), this was the main concern from the journal. Or at least, this was my impression of the journal's concern. I'm sure they want to avoid exclusively AI processed reviews. In fact, that may be the real concern, but it might be easier to get compliance if you pitch this as the reason. Also, authors can get skittish when it comes to new technology that not everyone understands or uses. Having a blanket ban on LLMs could make it more likley to get submissions.