I have a couple of related questions, one of which is a concrete question and the other of which is more general/abstract. My first question is in regards to the following sentence, which was taken from a government poster (USPS Poster 7):
Photographs for news purposes may be taken in entrances, lobbies, foyers, corridors, or auditoriums when used for public meetings except where prohibited by official signs or Security Force personnel or other authorized personnel or a federal court order or rule.
Namely, is the phrase "when used for public meetings" modifying just "auditoriums" or the entire list? It would seem that public meetings would be most applicable to auditoriums (though certainly not inapplicable to the others), but, knowing bureaucracies, I'm guessing that "except where prohibited..." is intended to modify each element of the list.
Further, in general, is there a way to deduce from grammatical construction (perhaps, additional commas), and not simply context/intuition, whether a modifier at the end of a list modifies the entire list or simply the last element?
Thanks for your insight.