Less nefariously: it's a poetry slam, organised in their spare time and making no profit, and they don't want to go to the effort and expense of getting a bank account, setting up a merchant account, and buying a card reader.
Got a bunnings snag and a couple raffle tickets today. Had that familiar mild panic at the back of the brain as I walked up and couldn't immediately see the card reader. All good in the end, the raffle tickets were disguising it.
ps, the bunnings snag was delectable. No word on when i'm going to pick up my prize yet though, maybe they're having dinner then calling..