For instance my company (Glowing Plant, YC S14) is entirely predicated on such an understanding. We read the rules and realized that if we engineered a plant with a gene gun instead of agrobacterium it would not be regulated in the United States. This saves us millions of dollars in getting a product to market and means we can pursue an agile product development strategy. Game changer.
I'm aware of another 4-5 such opportunities for syn bio products where you can get to market for low or zero regulatory permission.