Thankyou Alan! :)
Note that I'm not in favour of overly loud gigs.
I've been to many gigs where the bands been too loud, both in pubs (guitar has 4x12 and a Mesa, bass has 8x10, all drums miced up etc) and large venues (Airbourne at the Academy, where the sound engineer should have been shot).
And in fact, as has been said, larger venues should have the technology and the already have the compulsion under existing legislation to keep levels fairly cool, and still deliver great sound. Journey at Manchester Apollo was a good example; perfect with no earplugs in, loud but crystal clear.
No, it's pub and small club gigs that will suffer :(