Perfect Tommy: Eight plus years is pretty good for a cache to survive in a teen hangout. The purple path goes right by the hiding spot so it was just a matter of time. Further, the graffiti that was the initial point and hint have weathered away or been obscured. Finally, with the resurrection of Garvus' puzzle cache, makes sense to archive this rather than have two mystery caches share the exact same header coordinates...
Thanks to all that visited. Sorry we lost the logbook...