When my kids log into their accounts, in most cases they cannot start any application (not even TextEdit) since I installed Online Family. The app icon will only jump a few times in the dock and then stop.
In those rare instances when they can start an application, Safari will allow access to blocked categories, when started immediately after login. Only when they wait for about 10 minutes before starting Safari, the rules seem to take effect.
Setup:
MacOS 10.5.8, latest Online Family (via Live Update), limited user accounts for the kids with access to certain applications only (including Safari and Textedit).