Are people also not technically allowed to use a prepaid credit card registered in someone else's name? A parent could activate the card and then give it to the child.
You could, but then you're still paying fees designed to exploit the unbanked. If the parent is financially secure, they can use that fact to get a free checking account for their child.
In the US most bank checking accounts have a monthly fee which is waived if you meet certain conditions, like maintain a minimum balance (I think mine was $1000) or get an automatic direct deposit at least 2 times per month of $250 or more - these would be hard to meet for a childs account. Credit unions are usually free though.
There is usually a "relationship waiver" that eliminates the fees on all the accounts you're party to as long as you have enough total wealth parked with that bank.