This law has been around since Biz's "I need a haircut " album.(The album that brought the whole sampling thing to the forefront.
Album notes
Recorded At BMV Studios, New Jersey.All lyrics written by Biz Markie.Unfortunately, I NEED A HAIRCUT is best remembered as a record that made things difficult for rap artists. After the album's release, Biz Markie was slapped with a lawsuit by Gilbert O'Sullivan for the unauthorized sampling of his "Alone Again Naturally" on the Biz's "Alone Again." Sullivan won, the record was pulled, and a new ruling prompted all record companies to clear hip-hop samples before their release on record. Following this fiasco, Biz Markie slipped in popularity, and has kept a low profile ever since.
The thing is HipHop was never supposed to go beyond the ghetto. Hiphop was alive for years before the mainstream even caught wind, and even longer before they started to pay attention to it. Sampling was done soo tastefully and "broken down to its very last compound" that copyright owners never had a clue. It wasn't until BIG dollars were being made that anyone paided attention. Now that Rap is the number one money maker in the world, here they come.
If you sample keep doin ya thing. They Will Never "Shut it down." Heres a list of a few people that's hard to clear samples of...
http://www.onestopbeats.com/samples.html
BTW. Its not the artists that object to being sampled....its the greedy copyholders. Remember, 97% of the people you sample don't even own their own masters....PAY ATTENTION YOUNGENS.....Most artists were cheated out of their ownership rights(or just sold them not knowin)