No way, no how could I imagine taking my 5 yo to a rock concert.
Because:
1. It ain't the $5 movie ticket to get in...you are talking blowing another $100 on ONE ticket.
2. I think it's way too long to sustain a 5 year olds attention (and I work with them too!).
3. I think the things your child may see/hear when his/her attention is waining are going to be things you wouldn't want them to see/hear at the age of 5.
4. I think the crowds are too much for a 5 year old.
5. I think we are asking kids to grow up too fast these days anyway, why contribute to that?
Not to metion the pot smoke floating around