But Copilot won't accurately tell you if it's directly copying code, and if so what the license is. If it provides MIT licensed code that I then need to include, how do I know that? Do I need to search for each set of lines of code it provides on GitHub?
When a person gets code from another source on the internet, they generally know where the code has come from.
In a real world scenario you wouldn't be mindlessly pressing Tab right after linebreak and accepting the first suggestion that comes your way. While entertaining, nobody gets paid to do that.
What you get paid is to write your own code. When you write your own code, generally you think first and then type. Well, with Copilot you think first and then start typing a few symbols before seeing automatic suggestions. If they are right, you accept changes and if they happen to be similar to any other code out there, you deal with it exactly the same as if you typed those lines yourself.
When a person gets code from another source on the internet, they generally know where the code has come from.