It is in tons of case law involving unaccompanied minors. There is actually no new law on this, just someone figured how to connect dots on existing law.

This was going on with a lot of European Jews leading up to WW2, Nazis were not strong on interrogating children to determine ethnicity, and my grandmother had been able to travel as a teenager through Nazi Germany, neither were US Authorities or neutral country authorities, so the cheapest way to get someone in a family rescued or out of a conflict zone was to send the kids on their own, and most civilized countries maintain that unaccompanied children go into the foster care /orphanage system. Nobody does organized infanticide and if a country ejects unaccompanied children and refuses care, it is seen as heartless and barbaric. The US State Department would never live it down in the eyes of the Europeans, or any civilized country.

The Irish were known for this in a few immigration waves, buying passage for children to get them out of the UK where their expected lot in life was to beg, someone would scrape passage for them to get on a Steamer, with the hopes that whatever life they had in America was going to be better odds than in Ireland during the potato famine. Quite often a 13-15 year old looking after younger siblings.

Individually, shit comes down on municipal agencies even if someone figures out unaccompanied minors are begging on the street, and if some law enforcement organization were to come down hard on someone helping children like that, the Vatican would roll down on them so hard, it would not be pretty.