If only this was a true statement. It may be true for you, but it isn't for every one.
We out cross as much as possible if not every time. We also selectivly breed and take the longer rout when working on our projects. It's not necesarily how many generations that you line breed but how many times its been done before you and then after you that you need to think about. They say it takes 13 or more generations in BP's before some thing bad might pop up. How many generations did the breeder you buy from line breed for your snake? How many times did the breeder before linebreed? Before that?