Facebook not being blocked

I have set Facebook as a blocked site under the Web tab of Settings and have set social networking sites as blocked yet she has accessed Facebook eight times recently on her Android devices.  How is this happening?  

I have discovered how this is happening. Her htc phone has a built in Facebook app. I assume only installed apps show up on Norton because built in apps can't be removed without rooting the phone.Because she is using the app not the Web to access Facebook I can't block her.