When I posted on here my intention to file a lawsuit against a band that caused my tinnitus, I was met with very negative responses.
I found that incredibly frustrating as I was injured at no fault of my own. There was no warning, no protection provided, and I was injured.
The fine print on a ticket is not a legal defense, assumption of the risk in not a legal defense (unless there was a warning posted and protection provided). Hearing damage is caused without the feeling of pain, and therefore pain isn't an indication that would normally help you avoid injury, such as heat from a fire. Prior exposure to noise isn't a defense unless it made you aware of the potential of injury.
These are difficult lawsuits as it is fairly new territory and sadly most people don't understand how distressing, depressing, and life changing tinnitus can be, so damages aren't very high on average.
I really believe the concert/festival industry needs to change their behavior, protect people's hearing, and at a minimum warn people of the danger and provide earplugs. It'd cost them 50 cents a person at most to protect patron's hearing.