I was in the dignitary line for the USA Russia hockey game in 2002 Olympics (volunteering was really good to me). Started telling the guys behind me that I liked what I saw of playoff hockey, but didn't really understand the rules.

I asked if they knew the rules of the game very well. They chuckled and told me they were NHL referees. They gave me a NHL referee key chain as a memento of this embarrassing story. IT was a metal imprint of whistle and NHL logo

They never said whether or not they knew the rules well.