Thanks. I didn't ddg hard enough. r/chess tells me part of lichess' cheat detection is similar to my hunch.

So maybe my only novel suggestion is running lichess (or equiv) live in parallel. Something livestream viewers could also help with.

And I hope someone's replaying historical games.

"how a deep search is needed to evaluate"

Of course. Obvious now that you mention it.

I assumed different programs would make different suggestions. So overseers would want to run a few programs to see if any matched the player's gameplay, style, etc.

Probably the last time I played chess was on an IBM PC XT. The quality of misc game engines varied widely. Of course there's probably been a convergence since.