I've been finding co-pilot really useful but I'll be pausing it for now, and I'm glad I have only been using it on personal projects and not anything for work. This crosses the line in my head from legal ambiguity to legal "yeah that's gonna have to stop".
I suspect he has a different problem which (thanks to Microsoft) is now a problem he has to care about: his code probably shows up in one or more repos copy-pasted with improper LGPL attribution. There'd be no way for Copilot to know that had happened, and it would have mixed in the code.
(As a side note: understanding why an ML engine outputs a particular result is still an open area of research AFAIK.)
If your standard is “Github should have an oracle to the US court system and predict what the outcome of a lawsuit alleging copyright infringement for a given snippet of code would be” then it is literally impossible for anyone to use any open source code ever because it might contain infringing code.
There is no chain of custody for this kind of thing which is what it would require.
You might think it's unreasonable to build such a house-burning robot, but you have to realize that I actually designed it as a lawn-mowing robot. The robot will simply not value your life or property because its utility function is descended from my own, so may burn your house down in the regular course of its duties (if it decides to use a powerful laser to trim the grass to the exact nanometer). Sorry neighbor.
What do you expect me to do? NOT build this robot? How dare you stand in the way of progress!