What is this “fly in” in Wisconsin you speak of? Every year on the last week of July? Never heard of it. Never noticed an increase in private air traffic through Cedar Rapids that week during my career. Never did I notice that week 1) more non-talking non-participating radar blips and 2) more pilots uncomfortable and unfamiliar with ATC going past.
Just kidding, I did notice. Practically saved a guy’s life one year during Oshkosh, I was training a new controller on radar and he terminated service on a pilot leaving our airspace, but I saw another target basically head-on a few miles ahead descending right at him. So I jumped on frequency to give him a traffic call - he not only excitedly responded a bit later that he had the other plane in sight, he called back when he was a few miles further along to thank us again because it was pretty close.
Anyway, you probably didn’t know the Cedar Rapids ATCT tower manager is the manager of Oshkosh’s “temporary” tower operations this week. (Oshkosh has its own tower, of course, but for EAA the FAA recruits federal controllers from all over the country to come in and staff it for fly-in week.)