$ sudo rm -rf /
    rm: it is dangerous to operate recursively on ‘/’
    rm: use --no-preserve-root to override this failsafe

Relatively modern distro, but this has been in coreutils for awhile (it was fixed in Ubuntu's coreutils in 2008 for instance)

    $ egrep '^(NAME|VERSION)=' /etc/os-release
    NAME="Red Hat Enterprise Linux Workstation"
    VERSION="7.2 (Maipo)"

Yes, I just did this on the workstation I'm typing on. I'm somewhat curious if he did that on absolutely ancient distros (>8 year old), or didn't actually run rm -rf, but the ansible python equivalent.