But I expect instead of embedding such a signature they will just save hashes of generated content and sell a billion dollar “checking” service to schools.
We need to stop trying to get education on the cheap and put enough real, motivated, and properly trained humans in place to do it properly.
I think we’ll end up seeing two changes: restricting things like school or hiring to favor in person, dynamic interactions - which is better in many ways but costs more and has downsides for people with social anxiety - and more pressure to make the internet less anonymous, especially if that’s linked to physical devices similar to what Cloudflare and Apple have been doing to prevent the bulk attacks (it wouldn’t help much with a cheating student). Depressingly, all of that seems expensive and likely to have substantial collateral damage.
OpenAI did hire somebody who is investigating watermarking the output of models like GPT-3, so it's definitely possible.