I’ve been seeing social media posts of people doing this. Not sure what the background behind it is.
Edit: Here’s an example of what I mean: http://www.walmart.com/ip/All-Black-American-Flag-3x5-Ft-US-Flag-2-Pack-UV-Protection-Flags-Heavy-Duty-Embroidered-Stars-Sewn-Stripes-Brass-Grommets-Outdoor-New/828247324
There's a saying that I'll butcher "there's a point in every man's life that he needs to hoist the black flag and begin slitting throats" not sure what this for sure.