I guess the question is, how can a player know if an area was designed as a bunker, or as a waste area, if the gallery is allowed to walk there, and there are no rakes?
Unless it was also clear that there were no areas considered waste areas on the course? or that any area with sand was to be considered a bunker?
Not only allowed to walk in the bunkers but also allowed to stand in them while a player is hitting. I imagine it would've been hard to identify that as a bunker even without spectators covering most of it.
That local rule reads to me as if they are primarily addressing the issue of relief, not what is and isn't a bunker. A sandy area caused by spectator traffic would not fall under the definition of a bunker in that local rule, as it would not have been a designed hazard.