Has an Olympic Hockey (Women) game ever ended 18-0?
Exactly once. On February 13, 2010, Canada beat Slovakia 18-0, and no Olympic Hockey (Women) game before or since has ended that way. When it happened it was a scorigami, the first 18-0 in league history.
That makes 18-0 the 27th most common final score out of 41 that have ever occurred in Olympic Hockey (Women). One point away, 19-0 has happened never and 18-1 has happened never.