I can't understand anyone not choosing to wear earplugs. I guess not everyone will lose hearing capabilities at the same rate, but this is not something I really want to test.
Even more, I can't understand why bands like Mogwai, or the venue/promoter, are not offering free earplugs at the door. Some bands did that lately, although I can't remember who. This is not an issue for most regulars here, but I didn't wear earplugs for my first two years or so of shows, assuming that "adult" promoters would not allow unacceptable levels, but now we know that no one really cares about that.