Is the content on the tablet 100% child-friendly?

We are constantly working hard to ensure our content of family friendly. The controls we have in place are that the device cache is cleared after two minutes of activity to protect the users identity and remove their profiles. We also control the apps that we download so they are ones approved by Mums.net and have appropriate ratings on Google Play store. We also have internet content filtering through the Wi-Fi that blocks inappropriate content and is up to Mums.net standards. Dining area staff are trained to clean and press the logout button when not in use.