The fairness of a competition and the fairness of asking a particular question are different.
When things are just for fun, the impact of having unfair questions than when unfair questions can cause people to fail a class or get a lower GPA. This is why sometimes these kind of unfair questions get designated as extra credit as its unfair for these questions to actually count against you.
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Depends on your sense of fairness. Math Olympiads don't test what's in the book, but they are also fair.
The fairness of a competition and the fairness of asking a particular question are different.
When things are just for fun, the impact of having unfair questions than when unfair questions can cause people to fail a class or get a lower GPA. This is why sometimes these kind of unfair questions get designated as extra credit as its unfair for these questions to actually count against you.