But I would still write SOS or HELP.
You can imagine the scenario: “Hey Jane check out that - looks like a V in the sand” “Heh yeah”. “Weird”.
or
“Hey Jane does that say HELP?” “Heh yeah. Wanna check it out?” “Yeah let’s take a look”.
I am from Europe, though, so I don't know if it might be more specific to Western culture. Although I also imagine pilots would have more of an exposure through either experience or education.
At least all cultures who listen to ABBA https://www.youtube.com/watch?v=cvChjHcABPA
Three dots in a triangle, three flashs in a row, etc.
Its just easy for the human mind to detect it as an unnatural pattern.
It still probably better to use SOS or help but sometimes that's not an option.
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I for one, would investigate three triangles in the sand in a remote area. It might be a fun art project for that back country woodsman, but it's much, much, more likely a distress signal, whatever form it takes.
A lot of hunting regs also limit you to 2+1 rounds (2 in mag, 1 in chamber) for sporting purposes, so firing off 3 rounds also implies you're deliberately emptying your gun.