I followed through to a linked article from this one ( https://medium.com/@david_hewson/never-quote-a-rock-lyric-in-a-book-unless-you-re-rich-e39d53f85e7c#.whzk

I followed through to a linked article from this one ( https://medium.com/@david_hewson/never-quote-a-rock-lyric-in-a-book-unless-you-re-rich-e39d53f85e7c#.whzkywtdl https://medium.com/@david_hewson/never-quote-a-rock-lyric-in... ), which left me confused. IANAL, but I consider myself reasonably well-versed in common forms of copyright issues. I don't understand how quoting a single line of lyrics requires permission. Is it just the (unfortunately) normal "They'll sue you and it's not worth the expensive of a defense" condition? Or was there a case that decided this? While I'm aware that a cultural reference isn't covered under fair use defense, I'd argue a cultural reference isn't a derivative product either. Anyone have some data here?