To be fair, Pharrel and Robin Thicke [actually sued them first](http://www.vulture.com/2013/08/robin-thicke-pre-sued-marvin-gayes-family.html) once people started to notice what a ripoff the song was.  If I were Marvin Gaye's children, and somebody stole my dad's song, and then sued me, I'd be pretty pissed too.