It is odd to think of this but it must happen all the time.
Not many artists write their own beats or lyrics these days. No surprise that they are auctioned off to singers/rappers. Some artists will actually write songs for other artists only to be rejected and later end up singing them themselves. Two examples in the video are Sia writing a song for Adele, and Pink writing a song for herself but later giving it to Adam Lambert. I find this all very interesting. The music industry is more of a business then it would appear. Very cool though.
Number 2 kind of shocks me. I can't blame TLC for not liking the lyrics. They don't sound right. lol