Is this only for people entering the country or does it also apply to those in transit?
Quick google search brought me here: https://www.tripadvisor.com/ShowTopic-g1-i10702-k10297825-Do...
LHR-LAX-AKL requires all passengers to get off but those not terminating in LAX stay in a transit area (although there's still an immigration check).
And IAH supports international transit for bags, but you as a person still need to immigrate the normal way.