Erm, it seems you were not well taught about the role of intonation is expressing syntax. A compound noun is not the same as a {modifier + noun} phrase. I don't know about your dialect, but in all the varieties of English I've ever heard {modifier + noun} and compound noun have different intonations, even when the first element of the compound noun is an adjective, as in 'black bird' vs 'blackbird'. NB that when 'black' is a modifier it gets somewhat less "prominence" (to use your term), whereas when it is the first element of the compound it gets markedly more "prominence".
Actually, you can tell whether the speaker thinks of "spring switch" as a phrase or a compound by listening to how he _says_ it. Ignore how he writes it -- in English, there are no rules about how to write compound nouns. In general, long established compounds are written as one word, but new ones are not. Some people like to use hyphens to mark a compound noun (a hyphen is a spelling mark, not a punctuation mark, BTW, despite what your school grammar text told you.) There are also cultural differences: Americans don't like to write compound nouns as single words, so they usually don't. They don't like commas, either. These two quirks often require one to reread a sentence written in American.
If you really want to understand all this, I'll give you a lesson on the English noun phrase, which is a thing of beauty and joy forever. ;-)
HTH