22. Economic Nondiscrimination.
a. It will make the airport available as an airport for public use on reasonable terms and without unjust discrimination to all types, kinds and classes of aeronautical activities, including commercial aeronautical activities offering services to the public at the airport.
Airport Improvement Program Grant Assurances for Airport Sponsors, May 2022
"...reasonable terms..." - ambiguous, yes, but a grant assurance airport is expected to cover its nut, not become a massive profit center (airport revenue is expected to stay with the airport, not be diverted). The presence of a special event does not change what consititutes "reasonable," except to the extent the event actually increases the cost (per user) of operation. With a large volume of additional ops, the cost per operation could actually go down.
Edit: Note - this is mere recital of summary assurances from sponsors to the feds, but there is both rulemaking and statute to back it up. I'm tired, though.