Don't let your fair cause make you believe that restricting freedom is an option. Authoritarism is not only represented by the state. Exercising authoritaritarian behaviours while promoting freedom money is not only ironic but sad. Tickets is one thing, still done outside, ok. Letting people inside your venue without telling them they cannot buy without BTC (being unable to exit the venue to buy a snack or drink outside) and accepting only BTC (that you sell) is plain wrong. Is forceful and agressive. Luckily i had my Bitcoins, but refused the policy. Many people who were just there to learn could not.
Discussion
If you attend a football match will you complain about being forced to watch football?
Radical oversimplification. There’s one clear proposal in a football match all presented at the time of buying the ticket. I am not forced to anything. There are lots of things to do in a good conference but being subject to manipulation from people pretending to promote freedom doesn’t looks like something you should be proud of accepting. There are better ways to make money or push for ideas than being an authoritarian. But that’s just me and that just you! Have a great say!