Not sure what you are referring to
@peterbells? There is a modern tradition of leaving a stone at the Iron Cross as a symbol of a burden set down and left behind you as you continue your pilgrimage - endless seeming debate here has never identified the roots of that tradition. The Way, the movie, planted a notion of the camino as a reliquary process in the minds of many but the
Camino de Santiago was, historically at least, a simple pilgrimage to the shrine of the apostle - Spiritually rewarding perhaps but containing no particular relationship to those gone before or beyond.
The OP recycled an oft discussed topic: people putting stones in piles for aesthetic/ un-aesthetic reasons. Nothing to do with how you or anyone else might choose to memorialize their dead.