[otterley]

Most of these implementations actually kill all processes in the namespace, not just init. First, there may not be an init (the root process could be the service, which is actually a best practice with respect to containers); and second, the signal may not be propagated to its children, especially if a non-trappable signal (e.g. SIGKILL) is sent.

[asdfaoeu]

A sigkill is sent to everything in the namespace if the init/root process dies anyway. So effectively it is auto propergated.