Yes. Parents/guardians should always be aware of their child's actions.
The child legally gave it away. Nothing illegal. It belongs to child, not the parents. Child gave it away. Parents can't do anything, it's NOT theirs.
Parents, should talk to settle problem. If a big ticket item receiver parents should question it. (if stolen property, found, gift, how it was obtained) receiver or parents are not obligated to return.
Gifter parents may request item back, but not expect it back. Item is NOT STOLEN, but a gift. All they can do is punish child to prohibit such actions in future (child should go to parents first, before such action)
I heard of more expensive things being gifted.
Smartphone, tablet, game systems...