You're not thinking...I know you don't seem to get it, but if you are going to do ANY type of public event, you have to secure the necessary permits....
there are no loopholes to this. Any form of EXCHANGE for homebrew is considered illegal under the 1978 repeal of the ban on homebrewing, H.R. 1337...unless of course you become licensed to do so, and pay taxes.
That's the bottom line, folks.
Whenever a thread like this, or someone trying to make money off homebrew for whatever reason, charity or otherwise, all these "armchair lawyers," come up with all the ways they think could be "get arounds" the law. Sorry kids, you can hypothesize all you want, but do you notice ever any actually attorneys with knowledge of the law ever coming up with some of this stuff? No.
Whether we agree with the laws or not. You can't loophole your way through this. The laws are pretty specific in regards to homebrewing-
any medium of exchange, be it money or barter involving homebrew is illegal. EVEN FOR A CHARITY.
Remember homebrewing wasn't re-legalized after the Volstead act was repealed in 1933,
it wasn't legalized until 1978, and it took a lot of work in those 45 years to get it to happen....and despite it's federal legalization, it is STILL on a State by State basis.
It was legalized in Utah JUST a couple of years ago.
Do a little reading on the history of prohibition and the legalizing of homebrewing, and maybe you'll quit the idiotic hypothisizing about trying to get around the law, and realize what a fine razors edge this hobby sits on to many folks.
Read this for some enlightenment...It was one of our members trying to do a non-profit event,
https://www.homebrewtalk.com/f19/ohio-university-homebrew-festival-shut-down-140105/
This thread has all of the links covering the bill that legalized Homebrewing...it is a good resource and a very good read.
https://www.homebrewtalk.com/f14/history-home-brewing-legalization-u-s-seeking-info-194974/
If you want to do this, contact the local liquor control commission, find out the laws, and follow the legal process and do it. Get all the insurance and permits required if it is even legal to do.....You're dealing with liability and tax issues....
The argument as to whether or not the cops will or will not enforce it is kinda moot, because it WAS enforced in the Ohio University incident....