I think that first we should figure out that whether the competition the Jocks are talking about, is a Jock-exclusive one or is it a Campus hosted competition.
A College conducts many sports competition. One thing to note is that a Campus Concert is coming soon, which Jill is preparing for. Now there is a high chance that after this Concert, next might be a sports competition. These things are a Fun part of college life. Sports-meet, Campus fest, etc.
Jocks are on a sports-scholarship. If they do well in the Sports competition, they will get benefits.
This would make more sense that the competition they talk about is hosted by the Campus.
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Now If it is a Jock-exclusive one, do they have it every year?
If yes then they wouldn't be so free and focused to conduct it every single year, Conducting a competition is no easy work and the competition they conduct won't be on a big scale for sure. We know Jocks personality. None of them are smart except for Big A.
I believe that the competition is Hosted by the Campus.
As for the Prep part, I believe...that Chess is a sport that Rich Families love to play. I know golf and other stuff, But chess...It is played a lot in Rich families. Preps could have a chess competition as well.
Campus Concert + Free-Roam events