Sure; companies would expect their employees to check the license. Remember that a lot of them consider GPL (especially AGPL) software "radioactive", so it will still effectively dissuade them.

However, it is likely that many engineers will skip checking their sources. I guess for this to work Copilot should include the attribution automatically in a comment.

The real problem is that doing this is not possible for Copilot, because the tool itself does not know the source.