We just got back from the Carnival Victory with a 9 yr old. The groups are 6-8 and 9-12. Me personally, I think there are too many "non supervised" activites. Like autograph hunts, scavenger hunts, etc....The supervised activites are okay. But there are sometimes 200 kids in an age group. Last week there were 200 9-12 year olds and 200 12-15 year old. That's alot of kids to keep occuppied.
I agree that there were to many unsupervised activities. When we signed our 11 year old up, I told them that I did not want her to check herself out and they told me that they could not enforce that. I once overheard the counselor telling the kids that were getting ready to go on a scavenger hunt "do not come back before 10:45 and it was 9:00". It worked out o.k. as we told our daughter that she had to have a buddy in order to check herself out. She loved it.