You can automate this process by providing existing GPL source code and see what CoPilot comes up next.
I am sure at some point it WILL produce exact the same code snippet from certain GPL project, provided that you have attempted enough times.
Not sure what the legal interpretation would be though, it is pretty gray-ish in that regard.
There would always be risk for CoPilot, had it digested certain PII information and people found it out...it would be much more interesting to see the outcome.