Is it safe to remove power from a linux computer in run level 0? [closed]

I am working on power supply to a Raspberry Pi where changing the state of one of the GPIO lines shuts off power immediately. Is it safe to do this in run level zero, or is there more shutting down to be done from there before power off? If not is there a better place to do it?

The reason I ask is because the Raspberry Pi is an embedded system that cannot turn off it's own power. Power down is usually done by the operator switching it off at the wall, but in my case it will be part of a remote battery powered system where it is not required to run all the time.

Solution 1:

If the system has reached runlevel 0, it can be safely powered off. Not so many years ago, before ATX, you had to turn off a PC system by hand because it couldn't power down itself.