Will suggested that it might be:
Should we be open to question about our ethical purity if we quote from a newspaper in our sermon or use brand names in our allusions to popular culture? How about if I read out the lyrics to a popular (or unpopular) song? What about if I hum the theme song to a TV show to make a point?
Can anyone confirm this on the basis of Australian copyright law? I'm not interested in what you think should be the case but what legally is the case.