I have a 7 year old, and I was really considering bringing him to one of the shows near here. It's a fully seated venue, and I had an extra front row seat. He wanted to go, and would have enjoyed it. For about ten minutes. I want to go there at doors, hear all the intro music, hear Kristeen's set, watch the videos, everything. I do not want to leave and take somebody to the potty six times. I do not want to listen to somebody whining he's bored after the third song. I do not want to worry about an invader stepping on my kid's head trying to assault Moz. And, I explained that since we're in the front row, there was a very real possibility he could get pulled up on stage because he is an adorable little thing, and that idea made him very nervous- he is shy. Don't want to traumatize him.
Also, I do not really want to address the question, "Mommy? What's a lazy dyke?" or anything else of that ilk. Morrissey's music is not really intended for 7 year olds. I'm fine with truth and full disclosure, I just like that stuff to come up gradually so I can explain things in palatable, comprehensible chunks.
We had a special "date" and I took him to go see Blue Man Group instead. He was thrilled and it was much more kid-appropriate. Although, They Might Be Giants are touring, I should look into that- my son loves them.
I think the very early teens are a good time to start going to shows- that's when I started, about 12.
So, as a parent of a child about that age, that's my two cents. Hope it's helpful.