In the sixties and seventies you didn’t mess with the U.S. Immigration. I know it from own experience, and they could have sent him back to Indonesia, but apparently they didn’t!
That’s the reason it’s such a huge mystery of this out of space person stealing his way into the W.H.!!
Back that time it was not that easy to get a refuge status here in the U.S.!!!
Maybe it was different for a child.
He was a minor. He was a human being, not a parcel. If his identity was in doubt, WHO would they have sent him back to? Re-address him to CARE OF THE AIRPORT?