If you have Spotify or Calm enabled, there's a hard-to-guess workaround to get to Facebook.
If a child logs out of one of those apps, then uses the Facebook login feature, then is a little creative, it's possible to get to Facebook.
They'd need an email (which they can't get to on Pinwheel) or someone else's log on. This means they would have to follow quite a few steps to actually make this work. Because of these reasons, we left this available on Pinwheel.
If you're uncomfortable with that, here's a list of the affected apps: