Has a World Baseball Classic game ever ended 11-0?
It has. 11-0 has been a World Baseball Classic final 4 times in 270 games. The first was Mexico beat Nicaragua on March 18, 2016; the latest was Panama beat Argentina on October 1, 2022.
That makes 11-0 the 18th most common final score out of 87 that have ever occurred in World Baseball Classic. One point away, 12-0 has happened 2 times and 11-1 has happened 4 times. Nearly all of its occurrences fall between 2010 and 2039.