It has been suggested I post this question here:
Similar to popular non-Norton AppLock Apps, could you add the feature allowing Norton App Lock to automatically lock apps when the phone automatically disconnects from WiFi on to a mobile network, for example when travelling away from trusted WiFi locations eg, home or office WiFi (were the people there are trusted too)?
Including this feature removes the risk of forgetting to manually turn on the Norton App Lock. It's an easy thing to forget leaving home or trusted office. If a thief snatches the mobile phone while using it, all the thief needs to do is keep a finger on the touch screen so it can't automatically lock. All the private apps are exposed - Facebook, Google Drive, email...
I know it is technically possible to include this feature on Android. Free AppsLocks on the market include this feature as standard.