That's actually part of a whole chapter in World War Z. A mercenary from the rich people's resort who later ditched them reveals that once the common people started showing up to their door rather than zombies, an immediate fight broke out between all of the residents and their staff, with most of them killing each other. The mercenaries refused to intervene because they were hired to kill infected, not normal people, and had no loyalty to the rich residents.

The whole thing was broadcast live because the owner of the resort wanted to flaunt their status during the great panic.

I've thought about that. Scare them all into hiding in their bunkers, and then never tell them that there never was a threat.

They can live in their precious bunkers, while we all go on with real life. 25 years from now, one of them will poke their heads out, and say "HEY! How long as everything been okay?" And we can say, "Since the day you people went into your bunkers, now get back in there!"

This should be nonnegotiable