check bags on NZ's "direct" flights between AKL & LHR remain on the plane at LAX, though can't imagine the distance of those flights would ever present a hidden-city opportunity

can't logically see any reason why LIR-MIA-SXM (for instance) with checked luggage would present any hidden-city problem at MIA

some people are just worried at complexity i suppose, but are unable to articulate the precise potential problem