What I mean by the above is that the "call" skill is much different than the "weather" skill. All Alexa has to do is have a confirmation prompt in the "call" skill and this wouldn't have happened. That is what extremely serious looks like. This is exactly the same as the phantom laughter incident from a few months ago. Alexa "heard" someone say 'Alexa laugh' and laughed, but that wasn't the user's intent. It was fixed by moving to 'Sure, I can laugh,' followed by laughter.
Voice UI is very hard and still in its infancy but ability for personal harm (physical or emotional) must be considered in these interfaces. Turning off the lights may not need confirmation but unlocking the doors or turning off the alarm probably should. Sending recordings or answering calls or even calling people should require more hoops or at least allow the user to control the risk/reward.