There is no way to ensure this, you need to trust on the buyers. I bought some scripts from the best's dev's from rAthena, Hercules and old eAthena members. And if I were retarded I could post them right now. But I have paid dearly for it and I am serious about my business. I recommend you put a good price, if your system is worth $ 100, do not exite in charge. If you do something good and it is cheap, this product has a high chance of being prostituted.