I tend to applaud parents who don't let a newborn "end" their social life. I have friends who had kids and I didn't see them for 4 years because they couldn't break routine and though their child would parish if not contained within a bubble.
To be honest - kids under 6 months old are extremely easy to look after. All they do is eat, sleep and s*** in a 2 hour cycle - the issue is that sequence continues throughout the night. You can basically take them anywhere without them being much of a nuisance to your enjoyment. You want to see a nuisance? Take a 2 or 3 year old with you. Total. utter. chaos.
I hear the concern re: ear protection - that's just dumb. I don't think jumping around poses much danger (despite popular belief by those people without kids - they aren't china dolls) and I'd love to believe we live in a world where you don't have to worry about being showered with beer cans, beer and debris at a sporting event (however, people are idiots).
I personally don't think I'd do it, but I don't think it's as bad as some of you people make it out to be.