Well, can they atleast tie their belts correctly? I saw a boy not much older than 8 years old with a red/black belt that was tied completely wrong. I swear I almost started to cry.
There are schools that produce very young black belts that are not Mcdojangs.They may not be able to defend themselves against a 200 pound man, but they have excelent technique and forms. And being able to produce this kind of young black belt reflects very well on the instruction available at that school, being that it takes so much more patience and clarity to teach children. Bottom line when picking a school, choose on the quality of the student, not their ages.
Oh, and if you really think about it, once a kid gets their black belt from a mcdojang most of them wouldn't stay around because they essentially got what they paid for. If its the same black belt kids coming back consistanly for months and years it gets less likely it is a mcdojang.
(and just if you were wondering, if I had a school, you would have to be very very good and mentally mature to get a black belt if you are younger than 15.)
My bladed nunchucks are super sweet.