Well, it's at least integrated enough to know when you select Reverse gear. On the other hand, I can't think of an elegant way to integrate a front parking sensor because you wouldn't want it to be active at all times when the car is in Drive. So a front sensor array would have to be controlled manually with a switch.
Nothing fancy in fact. It's powered by a tap on backing light, which only lights up in reverse gear. I agree that the front is much different.
Our Pilot has front sensors. I think they only activate when the speed of the car is less than 10 mph.