Unlikely this plan would ever be used, though some aspects are probably useful for general civil disorder.
I wonder what contingency plans exist for alien invasion? While we can’t be certain, that might actually be a possible threat. It would be hard to plan for.
Zombies can safely be assumed to have some subset of human capabilities, with additional resistance to injury and disease. Aliens? That’s wide open. Their physical and mental capabilites are an open book, and how far their weapons tech has advanced alongside the obviously much more advanced space travel might be impossible to predict.
The alien plan would be fertile grounds for research into rapid gathering and analysis of technical intelligence. How quickly we can do that could determine whether or not humanity goes extinct.
Of course, the aliens could arrive with hideously powerful weapons that just are not suitable for engaging humans or for use on Earth. I’m not talking something as ridiculous as Signs where the water allergic aliens invaded a planet that’s mostly water, but more subtle things like their rifles(or equivalent weapon) jamming a little bit more often than ours do. That could give us an edge, possibly decisive if similar issues exist with all the alien tech. It might turn out to just not be a serious threat when they turn up.
It’s just really hard to say with aliens, but still, it might be useful to work up some contingency plans for planning practice as well as developing intelligence capabilities.
Source: The Pentagon Has A Zombie Apocalypse Emergency Plan | IFLScience