This a follow-up question to In the USA, do parents have the right to control their children's possessions?,
The answer to the other question appears to establish that (in general, or at least in some states or by common law) minor children can legally own property, though interestingly, this may not include money or items the children earn through their own labor or efforts—it is primarily gifts that they can own, and those generally would only be special gifts, not normal household maintenance items given to them such as clothes or shoes. Parents also have some level of control over their children spending their own money (not the topic of discussion here).
My question is: given that once minor children receive a special gift it is theirs and the parents cannot take it, can parents legally prevent their minor children from receiving gifts in the first place?
Let's say Grandma wants to give $10,000 to Junior. Could the parents say “No, Mom. Either give the money to us and we will administer it, or Junior can’t accept the gift at all.”? This is not taking what Junior owns, it's preventing him from owning it in the first place.
If such prevention can be legally done beforehand, then consider further if the gift has already been accomplished. Perhaps Grandma has already placed one hundred crisp 100-dollar bills into Junior's hands (or, say she deposits money into his custodial bank account before the parents learn of it). He runs to Mom and displays the cash/balance slip saying, "look what Grandma gave me!" Has the gift been irrevocably given at that point, or can the parents require it to be returned or set conditions on the gift at that point, given this is happening the moment they learn of the gift and immediately after the giving?
If they cannot prevent the ownership against the child's wishes at this point, what if the parents convince the child to give the money back or give the money to them (perhaps operating under a mistaken belief about what is legal, knowingly or unknowingly communicating falsehoods about the situation to their child)? Could the child or the gift-giver later claim that the parents stole the money because the child didn't understand his rights at the time? It seems like if the law considers a child competent to receive and own gifted property, the child is competent to also give away such property, and if a child could legally refuse Grandma's gift in the first place (even if foolishly) then he can also give away Grandma's gift after its receipt (even if foolishly).
Focusing more closely on the quoted cases in the original question, one part may be relevant: in HOBLYN vs. JOHNSON, 2002 as recorded at law.justia.co (emphasis mine):
"As a general rule any property acquired by the child in any way except by its own labor or services belongs to the child, and not to the parent." [46 C. C. 1314]. . . . It furthermore goes without saying that a parent cannot deprive a child of its property except pursuant to law (31 C. J. 1011), and the fact that in this instance the father had the property in question assessed as his property could not affect the title of the children. In Banks v. Conant, 14 Allen (Mass.) 497, it was said: "In consideration of the duty which the law imposes on a father to furnish adequate support to his child during infancy, the services of the child during that period are due to the father, and, if they are rendered to a third person, the right of the father to recover the value thereof is clear and indisputable. But this is the extent of the father's right. He has no title to the property of the child, nor is the capacity or right of the latter to take property or receive money by grant, gift or otherwise, except as a compensation for services, in any degree qualified or limited during minority. Whatever therefore an infant acquires which does not come to him as a compensation for services rendered, belongs absolutely to him, and his father cannot interpose any claim to it, either as against the child, or as against third persons who claim title or possession from or under the infant."
Rephrasing this more directly, "the right of the child to receive property by gift is not limited or qualified in any degree during minority."
This would seem to suggest that parents may not interfere with gift giving to their children, however it is not clear. Does "the right to take property or receive money is not limited" assert that children must be allowed to receive any gift at all? Or is this only recognizing that, once given (a process that the parents might legally prevent, but did not), the parents cannot then take the gift after its receipt?
Imagine the parents believe all dancing is wrong, and a friend of the child gives him a book on how to breakdance. May the parents legally demand the return of the book to the friend?