China has had its own version for years, and it’s one reason why Americans adopt from China: no “open” adoptions.
NJ has this already; I think it is called something like the “safe haven” law. While it doesn’t involve boxes, people may dump their unwanted babies in certain places (hospitals, fire stations, etc.) with no questions asked. I don’t think it really took off; it seems “mothers” prefer closure to never knowing what became of their child, and prefer to kill him/her.
Sad...
In China, it is illegal and has been illegal to surrender an infant UNLESS the married man was widowed and couldn’t take care of the child. The baby girls (mostly) are secretively placed in boxes where they could be found... busy markets, outside businesses, schools, etc.. The parents (many times) will hide.. a distance away to see the infant is found.