I'm actually thinking that the "non-experts were no better than experts" bit is maybe a little misleading, as I remember seeing a lot of the non-experts base their predictions on what experts had been saying.
Really? That wasn't my recollection. But you probably saw the data more than I did, so I'll bear that in mind in future!
The new paper by Stuart Armstrong (FHI) and Kaj Sotala (SI) has now been published (PDF) as part of the Beyond AI conference proceedings. Some of these results were previously discussed here. The original predictions data are available here.
Abstract: