Don't forget that different countries have slightly different copyright laws!
The truth in the UK is that copyright is absolute - if you could identify any part of any published music that was composed/originated by someone else, they could have a case against you. In real life of course, it doesn't happen because most of us are not important or threatening enough. However, if you threatened my (or someone elses) business and livlihood by illegal use or copying, I (or they) might decide to have a go at you. If I thought you'd made money by your illegal use or copying, I'd want it . . .
But always bear in mind that most of our uses are really insignificant.
I try to make someone happy every day - but it may not be your turn today . . .