I thought the following Top 10 Tailgate Pregame Recipes looked very appetizing.
I especially like how the tailgate pregames parties create community for the game attendees and get all the vehicles parked way before the game starts.
The recipes follow:
https://barbecuebible.com/2019/10/25/10-best-tailgating-recipes/
Maybe the concessions could sell some items or services to make this tradition easier to maintain like selling sides such macaroni and cheese, coleslaw, gazpacho in drink containers, Greek salads, sodas, coffee drinks, team merchandise, and garbage and recycle take away.
Parking spots are numbered so this could be organized like curbside pick-up.
Leftover food could be sold through Too Good to Go or a similar organization.
Just a thought on a rainy day.
By Ruth Paget, author Eating Soup with Chopsticks and Marrying France and developer of the Novgorod and Bento War Games