@be Right. A vaccine requirement is great if an organizer wants to lower their legal liability from people ending up hospitalized.
But if they'd actually like to stop the pandemic? Masks and daily rapid tests to minimize infected people in the facility and the ability for the virus to spread. Not requiring a negative morning test increases the number of infections people at your event by 10-20 times.
Unfortunately the USA does not have a functional government currently; we can't even get it to peer status of compulsory for kids in schools like many other vaccines that don't have an active pandemic.
Sadly the USA also ignored the third year of the 1918 pandemic too; even the history books often don't talk about it.
https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html