"small group of people having this problem" ok...it's like more than half the users of xbox live that have this problem, they wont do anything, there was a big thing when msn came out for 360 and child accounts couldn't use it...just got to deal with it, or make a new account which i have done and i know it sucks cause achievements and all, but they are just achivements..unless ur crazy for achivements..
Yes you are stuck with it like everyone else is saying, but there are settings you can alter where you can have access to everything, such as friends list and all.
Im not sure exactly what it is but you can, while signed in through the parents .NET on the xbox you can edit the settings so your child account has full control over everything, the only thing you miss out on are the ads on the blades and MSN
i had this same problem. i ended up changing my account but u can fix it. if u remember the email and password of the "parent" account that u used u can login under that when you are under the parental controls option and change them. if u do not remember, then u can only make a new account. dont even both calling it just causes aggravation.