That is very true, I should have said most because I know there are some really nicely colored pastel and Patel combo adults out there, you just see a lot more that have either faded or became almost completely brown. If going the pastel route, it would be wise to see the parents if possible, it's not a guarantee but it will definitely give better odds of getting one that will hold its color well if the parents have.
i also take back that my pastel DG is the 'only' clean snake I have, I should of said it is the only clean yellow and black bp I have or have seen for that mater. There are quite a few clean morphs out there, they just are not yellow and black.