As previously anticipated, Google added a feature that lets you lock SafeSearch filtering. Google says that "SafeSearch screens for sites that contain explicit sexual content and deletes them from your search results".
SafeSearch could be easily disabled from Google's preferences page, so now parents have an additional safeguard: locking SafeSearch. Go to the search preferences page, click on "lock SafeSearch", log in to your Google account and wait until Google sets cookies for almost 200 domains.
"When you lock SafeSearch, two things will change. First, you'll need to enter your password to change the setting. Second, the Google search results page will be visibly different to indicate that SafeSearch is locked. Even from across the room, the colored balls give parents and teachers a clear visual cue that SafeSearch is still locked. And if you don't see them, it's quick and easy to verify and re-lock SafeSearch," explains Google.
The feature may seem clever, but it's not: you need to lock SafeSearch for all the browsers installed on your computer and for all the user accounts that might be used by your children. Another issue is that the lock can be easily disabled: just clear your browser's cookies. The colored balls are cute though, especially in a family-friendly context.