Even if it was a difficult operation to copy a song, it only takes one person to do it. After that the spread of the song via the Internet or other means of propagation is only limited by the honesty of the users.
“The thinker dies, but his thoughts are beyond the reach of destruction. Men are mortal; but ideas are immortal.”
“I definitely have a little attraction to bad guys, but they have to be sweethearts underneath. After all, I like to be treated well.”