In defense of Rufus Wainwright, a Canadian-American who sang the National Anthem at Dodger Stadium prior to Game 5 of the World Series, mistakes happen.
It's understandable that singing in front of 40,000+ fans can be daunting. Additionally, it seems many American fans didn't notice Wainwright's error.
A correct performance of the Canadian anthem on baseball's grandest stage is warranted and expected.
Wainwright surely knows the words or else he wouldn't have volunteered to sing the song in the first place, making the mistake unfortunate.
Author's summary: Rufus Wainwright's mistake singing O Canada.