I am already seeing ads for “private security services” in my area, & they don’t look like the old alarm system companies for your house & garage, or ADT or SimpliSafe. They look more like for real, ex-military type security services, which I predicted would come to this area, but I thought we’d have a collapse first - 
… YOU need to prepare accordingly and be your own private security service. Police or “private security services” are after the fact services. Should you decide to procure such ask them what their “average response time” is, double it, and that is how long you will have to fend for yourself. Just another “service” that will enrich them at your expense.
I’d also add that, although we have been conditioned to be civilized, in the situation that you’re describing… I personally wouldn’t be giving anyone in close proximity the benefit of the doubt.
In other words… I’m not sure warning shots should still be en vogue…To each his own though.
The MadMax series were training films 
… I make the same claim for The Walking Dead. 
Indeed to comments, predictive programming.