- Official Post
With a recent release of Raspbian it is possible to power on/off the RPi via a switch.
All that is needed is to have kernel support and then just add dtoverlay=gpio-shutdown to config.txt.
The overlay already exists in /flash/overlay so it just needs to be supported by the kernel.
Details of the overlay are Here
I've test this on Raspbian and it works fine.
You can add gpio_pin=xxx to use another gpio pin but only the default (pin 3) allows a power up.
I'm not too sure if it would work with LE but if it does, I'm sure a lot of RPi users would welcome the ability to safely power off/on their device via switch.