Responding to abilities/splash killing?

When an ability or splash kills a unit, does the Event Response "Killing Unit" work? Is there any other way a unit can die (Without triggers) and this not work?

Sorry if this is a noob question, I can't really test it easily.

If a unit starts a damage-over-time effect on some unit (like Slow Poison or Shadow Strike) and then that casting unit dies and is removed from the map. If the second unit were to die from the DoT after the first is removed, I believe there would be no "Killing Unit".

I don't know any situation when that event wouldn't trigger.

There is one strange behaviour of it though - if you kill the unit using KillUnit() (or its GUI counterpart Unit - Kill) the credit goes TO ALL UNITS ON THE MAP.