I like to make short films but I don't have the budget to pay for copyrighted music. In one of my first films I used some copyrighted songs and I ended up getting in a lot of trouble.
Unfortunately, non copyrighted music is often pretty anonymous and people don't recognize it when it comes up. It would be great to be able to use a Rolling Stones song but there is just no way.
It takes a conscientious filmmaker to be to use the music they find randomly, effectively in their film. I can be done, but you have to know what you're working with.