Why is administrator password NOT required?

My Macbook Air is NOT requiring a password to get into the Administrator account.

When I restart the Mac, it does require a password to get into both the Administrator and User accounts. I also need a password to go from the User account to the Administrator account. But once I'm in the Administrator account and start Screensaver, I do NOT need a password to get back into the Administrator account. In the User account after starting Screensaver I do need a password to get back into the User account.