I've seen more than my fair share of weird shit even before the world ended like a specific order of how you should move in items into your new home, spilling the first shot of an alcohol bottle on the ground in a drinking session, etc. but yeah, they were more regarded as customs in a specific culture—Filipino culture—but it takes a specific type of being fucked in the head and the obscure "arts" to do shit like this.
And god fucking knows what the purpose of this was other than an intimidation/scare tactic or cause people to straight-up question if they should be free to walk among us or should WE be free to shoot them in the head if we came across such people.