

On the beach I don’t know but depending on the area those can be trail markers and you should probably not knock them down especially in deep back country and instead pick up trash you find, otherwise people are gonna tie plastic or carve into trees to mark way points. Also at least in the united states some native Americans rock pile as part of their culture, I’m sure other places do too, as a jew I know I stack rocks on Graves so the rocks you knock over might be something important but I guess you are the main character so you do you
As someone who goes deep into national Forrest they are absolutely used as a trail markers, you may not like it but it’s a fact of life and better than putting a wooden sign up. And we are talking deep country not well beaten paths that are day hikes