Probably the default should not be None. There should be a mandatory license, either the Unlicense https://unlicense.org/ or something even simpler ("this is public domain".)
I'm not sure if unlicense/public domain would be a better default though. At the very least, that Github prompt should explicitly state with a warning what it means when you select "None" as the license. I think most people don't realize or know what it means for others who want to look at or use the project.