Atomic diagrams would be good for advanced societies, but societies in the bronze age or middle age advancment are the ones that we have to worry about. They won’t understand atomic phyiscs but they are capable of excavation. Any fancy symbols might just intrigue them.

I think they underestimated the intelligence of possible future societies. Any society advanced enough to excavate this will be intelligent enough to ask “what does this symbol logically mean”. They won’t be limited to the ‘bad-vibes’ that the current ideas are heavy on (language aside).

Why did pirates use it? Because it’s “give us your shit or you die.” Aka it was a symbol of death.

I think your fear is more likely with the current ominous but doesn’t tell you why message (if the language part is lost).

That’s just bones of a different nature. Any society capable of large excavation will quickly figure it out.

I was thinking about this and their thinking was way too complicated. The symbol you need is bones. Bones are always associated with death and decay because after death, bones are the thing that’s left.

And yes I know they thought of it but I think their dismissal of it is wrong. Their counter argument that it was once a symbol of something else by some culture, therefore. But again by its very nature it’s associated with death. Any society capable of this excavation is also capable of thinking “hmm what did they mean? outside of our own culture of course” and will quickly figure out it’s bad.