I personally expect the law to end up with a "safe harbor"-like situation. Consider YouTube. Occasional copyrighted content does not make YouTube illegal, or able to be held liable for slip-ups. See the DMCA as well, which requires takedowns upon notice, but otherwise provides near total indemnity for user-generated content.
Because of this, if the law looks at GitHub Copilot, I would expect that they would find Copilot to be A-OK despite the occasional regurgitation of copyrighted material that isn't fair-use, as long as it is removed upon request.
Because of this, if the law looks at GitHub Copilot, I would expect that they would find Copilot to be A-OK despite the occasional regurgitation of copyrighted material that isn't fair-use, as long as it is removed upon request.