Any lawyer will tell you if the first two points are unclear the third point is rock solid - don't use tools that have ambiguous copyright terms until AFTER the big legal fallout/legislation unless you are willing to bet the entire farm.
If the law is so unclear that lawyers can't determine legality and are waiting for additional guidance from the lawmakers, shouldn't it be legal by default?
A law like this seems pretty much impossible to enforce, though. Even if it turns out that GPT is just parroting remixes of GPL code, all examples of generated code I've seen are fully indistinguishable from code someone may have come up on their own - with the exception of contrived cases where someone is actively trying to get it to output a particular fragment of code verbatim.
My common sense says that without a tiny bit of doubt, copilot is utterly outlaw so far, essentially stealing gpl code where the only price was credit. It probably has several other problems but that is one that anyone can see. I don't mean everyone agrees, I mean the information needed to make the judgement is all present to all observers without needing to see the code or the training process or be a lawyer. There are countless examples of regurgitated gpl code, with no credit. End of search.
It's inexcusable because it would have been almost zero burden to get everyone's consent to be included in a collective credit. They didn't even do that.
So, whether or not this assertion of mine ever amounts to anything, it's a simple example of something being illegal all along, but maybe you don't know it until after you do it, and it gets examined and judged, and the judgement goes the way that burns you.
It doesn't require any new law.