Hi there, are you running 3.00 GoPro firmware? this can happen, random power on of the wifi. It will not happen when the GoPro is on but sometimes, it just turns on when the GoPro is powered off.
I notice it can happen if I try and power on the GoPro, then the Phantom 2 right after in quick succession, it will turn on the wi fi and not the GoPro, then the Phantom power comes on and the go pro reboots and the wifi is off and GoPro on this has happened twice in 20 flights. I run a cinema rental house (Revolution Cinema Rentals, see our upcoming event) with like oh 100 GoPro's some mornings you come in and they're just flashing at you with their blue wifi led's, maybe 50% of our are affected. I use a modified version of their firmware that we created for Need For Speed, It enables us to lock the ISO shutter speed etc, it can also be a bit buggy.. Ain't Technology fun!