As a human, I am likely to have the specific goal of not violating copyright when I write code. That means either deliberately not writing things exactly the same way that I know I've seen them written in other places or else deliberately complying with their license policy if I really want to lift code verbatim. Perhaps Copilot needs some sort of feedback loop to avoid over-similar code by default & an extra "allow (compliant) copying of open source" toggle to make it behave similarly.