I'm having some success at identifying AI by requiring students to write everything in Google Docs, and then using the Replay movie feature (set to 8X speed of course). Sometimes the AI prompts are right there in the paper, sometimes the entire thing is written without edits of more than a word or two (as the latest features of AI will write directly into docs).

Two round icons are in the sidebar, but we aren't allowed to share the screenshot in this sub, I guess. The pink "unknown" button means "Anonymous users are users who were not signed in to a google account when editing". Anonymous user edited 100%. Below that icon is my student's regular icon, it says edited less than 1%.

I'm guessing this means AI is the anonymous user?