That sounds like a question of degree for the jury — the evaluation of whether or not the facts presented warrant a claim of sufficiently infringing similarity. In this case the judge felt the plaintiffs weren't even close to demonstrating infringement that the question never appeared in front of a jury.
If we're moving the question to one of degree then it's up to Microsoft and others to monitor their output because even if a model is not trained on copyrighted material, you can still accidentally infringe. Even if you never listened to music near or by Lady Gaga, that does not mean you can use your own original inspiration to accidentally write songs that are too similar to Lady Gaga. In other words, like the Ed Sheeran case.
If we're moving the question to one of degree then it's up to Microsoft and others to monitor their output because even if a model is not trained on copyrighted material, you can still accidentally infringe. Even if you never listened to music near or by Lady Gaga, that does not mean you can use your own original inspiration to accidentally write songs that are too similar to Lady Gaga. In other words, like the Ed Sheeran case.