I can confirm that using this method does in fact notify the sender that you've declined. I've simulated a spam event simply by inviting a friend to an event, and then watching them use this method - moving it to a new calendar and deleting the calendar. As soon as they did this, I received a notification that they declined my event.
When following a similar procedure on the Mac using the Calendar app, I was presented with two options: "Delete and DO NOT Notify" and "Delete and Notify." I selected the former. I hope that the "organizer" of the bogus event was indeed NOT notified.