The way I tested this is installing mobile defense as a system app.
Background:
Mobile defense is a program that allows you to locate your cellphone (coarse and GPS specific), start an audible alarm and lock it down if it lost.
Problem:
Although is nice MD has a fatal flaw: MD can be uninstalled and/or the GPS can be disabled making the application kinda useless.
Solution:
if MD is installed as a system app, it will turn on the GPS on its own and it cannot be uninstalled
By using the FULL root method, you can, in fact, transfer the MD apk to the system where the user cannot shut it down (at least not if he/she does not know about XDA/PPCG).
The instructions (using method 2) are
here
Note that step 9:
would not work/spit an error about that location being out of memory if you were using the previous methos (Rooting step 1 only), now if you do this line again after performing step 2 of rooting the command will execute successfully confirming that the system partition can be written to now.