Smartphones and tablets pretty much all have GPS built in.
Mobile apps are commonplace for VMS systems but we are not aware of any that take advantage of the built-in GPS capability.
What if VMS mobile apps used the device's GPS to better manage / display cameras. For instance, the app could immediately pull up the cameras closest to the device to show the user what is happening nearby. Or the app could display a map, center it on the user's current position and show where the cameras are relative to the user.
Useful? Not useful?