>Or maybe they see it and think it'll make the sick well again.

I actually thought about that possibility. Figuring civilization will have collapsed several times, there's a good chance most people could look quite disfigured. I mean, post-apocalyptic wastelands can be harsh. At a minimum nobody will be exfoliating on a regular basis.

Then, if the meaning of certain common symbology happens to be reversed (e.g. arrows pointing away from the subject of interest), that's all it would take to mistake that image as marking the location of a miracle cure—a radioactive fountain of youth.