OK, I am getting a little worried about the security of macOS High Sierra. High Sierra encourages users to require a password to change System Preferences. That is a good security practice. A recent discovery has revealed that you can login to the App Store Pref Pane using any password you wish. I tried it, you can do it. Supposedly, this is corrected in 10.13.3. This article provides more information if you want a little more detail.