At the very least we need something similar to
chrome.extension.isAllowedFileSchemeAccess or
chrome.extension.isAllowedIncognitoAccessThat would improve the situation slightly, but it's still a problem because in addition to asking the user to grant a permission (the userScripts permission), the user must also follow instructions on how to enable a checkbox that's hidden somewhere in the browser's UI. This is a terrible user experience.