On OS X, administrative accounts still need to authenticate with their passwords to perform administrative tasks. This is to avoid (presumably) someone using yo

On OS X, administrative accounts still need to authenticate with their passwords to perform administrative tasks. This is to avoid (presumably) someone using your computer and changing settings without your consent if you have automatic login enabled, and to make sure you pay attention to what you're doing (similar to the UAC prompts on Windows, and sudo on Windows)