The company can't address this. I posted about this when i downloaded it. Guess no one read it.
The problem is with the phones, not the app. The phones battery life drains when the gps is left on and searching. It would do this if you just left your nav on all the time as well, it's not the Phoneguard app in particular.
The difference is when you typically turn your nav, you are in your car and can use your car charger. With apps like these, they need to be left on all the time so it knows when you get in a moving vehicle.
A fix for this would be for it to kick on and off based on cell tower triangulation. When it sees you are moving at a certain speed away from a tower or quickly changing tower to tower, it kicks on. Then when it sees you are at the same tower for an extended period of time, the gps turns off.
It probably wouldn't turn on as soon as you got in your car, but should shortly after.