Personally, I think if you have freestuff, you should let people make all the commercial renders that they want to. I am against someone reselling or redistributing the freestuff on its own - but the renders geez... that sorta goes against why you gave it out in the first place. I dont care how much you render, render till your socks fall off. If you manage to sell your renders, bravo - you must be pretty good at rendering then. I have made one freestuff, which I allowed people to do just this, anything you want, commercial or not. I didn't even want credit because it was a morph, and I didn't feel that I did enough work to warrant any credit (it was one of my first morphs and could have been better). I had to take it down later, but because of BANDWIDTH problems, not because of people using it. Its nice to give credits to people that have contributed a great deal to a piece, but I think this is simply nuts if its a small contribution to an overall work. And if its something you bought - thats even more nuts. I'd say if you gave it to someone to do product renders promoting the product, then YEAH they better put credits there... but when you bought it fair and square... no I dont think so.