You can't really "void the warranty" poking at Mac OS internals, and the built-in recovery partition makes it pretty easy to fix anything you break. Same as booting a BusyBox shell when you break something in Linux.

… though turning a car into a rocket-powered go kart seems like exactly the right analogy for running Linux as a desktop in my mind. Supercharged and able to fly, but not street legal or practical in any way.