A breeder in Florida discovers a new gene and calls it "mocha." A few years later, a breeder in Pennsylvania discovers a new gene and calls it "lavender." The "mocha" breeder suspects that the "lavenders" are actually the same thing as mocha and may have come from his stock. The result: years of arguments over the internet and a "scandal" that many breeders would rather forget. It eventually turned out that the lavender and mocha genes were one and the same. With pedigrees, this entire situation would never have started. It would have been quite obvious where the "lavender" gene came from.
A breeder notices a detrimental recessive gene, and culls all the ones who produce it. However, plenty of undetected hets may have been sold over the years. It was originally in snakes that had the sunkissed gene, and many hobbyists are now afraid to touch anything with sunkissed in it. In the meantime, snakes from that original sunkissed population have been outcrossed into stripe, charcoal, diffusion, caramel, hypo, lavender, anery, motley, and amel lines. Many wild-type grandchildren have already been produced, as well as various combinations of these morphs. The days of avoiding this bad gene, by just avoiding sunkisseds, are now over. With pedigrees, breeders who test and "clear" their lines--and those who buy pedigreed snakes, and those who buy great great grandchildren of those snakes--will be able to tell the clear from the potential carriers.