Security through obscurity would be having a system connected to a network, but relying on a secret / unknown protocol to secure it.
Air-gapping a system is a real and very useful security method. That being said, it’s not enough by itself.
If you’re interested, have a look at past examples, like the recent work on breaking Tetra communication standard and Stuxnet.
reboot -f
Because real men login as root and don’t care about such silly things like an init system or file system syncing!
To quote the man page: