Not to derail this, but I have to respond:
If most venues have volume limits, they are rarely enforced. Or if they have them, those levels are so high, that hearing damage can occur well below the threshold of that volume limit. That is particularly true of sports stadiums which are surrounded by acres of parking lots, which by their existence minimize the need to turn down, as there are no houses immediately adjacent to the concert, and therefore neighbors or communities are less likely to complain about noise.
With all due respect, that attendees don't bring lawsuits doesn't mean much as a validation of sound levels in stadiums as being "reasonable"- we seem to have many musicians on this board who have little regard for their own ears, despite the necessity to protect them. What makes anyone think concert-goers, in general (some of whom may and may not be musicians) would be more concerned about their hearing than musicians?
Regards.