I've heard of musicians performing w/earplugs but not concert goers?
The sound is there (profound statement, I know this!

), so you will go deaf if you're on stage or in the audience. If someone in the audience wears earplugs, then they are smart!
I remember this guy telling me one time that I needed to wear earplugs, and I brushed him off thinking "I don't need them, plus they look dorky!"
The reason I started to wear them, was because I was playing with the female singer. She was either an ego maniac (knowing her this is not a far stretch), deaf, or both! She would turn her monitors up so loud that I couldn't hear myself at all (not just faintly or "not as clear"....most musical newbies don't realize you WILL have to sacrifice SOME clarity once the whole "musical landscape" is painted). The worst part of this; I always stood within a few feet of her and her monitors would either be pointed directly at me (us) or I would have the sound bleed into my area.
The feeling was sharp, and painful. The only time I have ever had that experience with my hearing. The gigs were not fun to go to, and made playing the music worse, and my attitude began to show that. One day before a gig I was talking to my dad, and he suggested I get earplugs, to purchase them at the gun shop down the street. Best move I could ever do!!!
One night I forgot, or most likely lost one of the plugs on the drive to the gig. "Ah, I can test the ear plugs out!" So, for the first set, I played with the earplug in the left ear. My right ear is fine I thought-WRONG! Got off stage and when I pulled the plug out, the right ear was noticeably fuzzier and "compressed" sounding. The 2nd set, I put the plug in the right ear, and at the break the exact same thing happened to my left ear.
Moral of this long ass post...
No matter where you are at (audience, on stage, in the balcony etc...) you will be affected by the sound. Most don't realize it at the time, because both ears are affected. My little test I described above is what happens to all listeners at one time or another, but they don't notice the difference in their hearing due to both ears being affected.