In the past, people have consistently emailed to confirm that the application does not run in the background (due to bandwidth concerns). In fact, the app does not run in the background unless you are using home screen widgets or record mode (rate is adjustable).
Because of this concern, the closest to a baby mode was to run in Gallery View with Auto Dimming turned on (see App Settings). This way, you can hear audio and have a dimmed screen (for night time). The screen will turn on if touched or motion is detected.
However, there’s been an increasing email demand for another option to play audio even when app is not in the foreground and when screen is locked! This goes against the demand by other users to not run in background.
With Android v4.9.5, I’ve added a new Background Audio Mode option (in Gallery View, click Menu key). In this mode, and only in this mode, the app will continue to run in the background and play audio even when phone is locked (audio includes motion detection notification sounds if enabled).
In summary, the Android app will not run in the background except if you’re using widgets, record mode or background audio mode.
ps. the iOS version never runs in the background.