Just like all Apps that use Touch ID/Face ID login, this relies on the details that you have allowed to be stored on your device. By way of example, if you have stored a third parties fingerprint on the device then they will be able to log in to the Double Bubble Bingo App. This is essentially the same as giving them your password. Please ensure that you are the only person with access to our App at all times.
If you want to disable Touch ID or Face ID on your device altogether;
For Android devices, go to Settings > Security Settings and disable the fingerprint feature.
For iOS devices go to Settings > Face/Touch ID & Passcode.