Has an Olympic Hockey (Women) game ever ended 12-0?
Exactly once. On February 12, 2006, Canada beat Russia 12-0, and no Olympic Hockey (Women) game before or since has ended that way. When it happened it was a scorigami, the first 12-0 in league history.
That makes 12-0 the 27th most common final score out of 41 that have ever occurred in Olympic Hockey (Women). One point away, 13-0 has happened 2 times and 12-1 has happened 3 times.