Please respect the value of tradition.

Only when using GNU rm and its descendents, as far as I know. FreeBSD and OS X's rm neither require that option nor support it. Unless you're asserting that psgbg has never used a system with BSD userland (which includes some running linux kernels) and none of psgbg's theoretical hacker mentors have either, it's not a safe bet they'll need that flag (or be saved by its lack). If they'd stated they were manually commit rmicide on a linux box it'd be a different situation, but assuming tools have safety nets is one of those things that happens to sysadmins. Sadly it's done to us at least as much as we do it...

All that aside every unix person who wipes a box for a reinstall should try rm -rf / and see what works and what doesn't. It teaches you a lot about shell builtins, filesystem dependencies, binaries still running and thus hanging around in /proc & its equivalents (which can save you), and weird stuff like /dev/tcp/ and /dev/udp/ (if your shell has them and they're enabled). A Linux or BSD machine can often be recovered live from deleting everything but /home, say.