Financials is the big one I see. Relying on ticket sales to pay over priced bands they have booked in advance on the hope they will draw ticket sales for them then they fail and cancel last minute and blame it on something else.
I saved up for 2 years to put my first festival on, on the basis that I had all the money covered before a single ticket was sold, before a trader paid for a stall and before a sponsor was sought. That way it guaranteed the festival would happen. That is my biggest bug bear. I'd be really happy if the music festival industry could be regulated. I know that puts a lot of pressure on but if you are a small but hard working event with guaranteed finances, you suffer every time a festival is cancelled due to poor ticket sales. Peoples confidence drops.
We launched our festival off the back of a failed festival called Alt-Fest. It was supposed to be the biggest alternative music event in the UK. It collapsed due to bad funding management and other issues. But that created a big problem in the music scene as most people didn't get their money back. I lost £5,000 as my previous company sponsored one of the stages. We could have chased the liquidators but felt there was no point as there were bigger companies that lost a lot more than us.