What's right or what's wrong don't mean diddly squat unless you got the stroke to enforce it. If you haven't got the dough for lawyers, or hitmen, don't get upset when your license gets violated. All you do in writing up stringent controls on the use of your property is to set yourself up for frustration and anger. Citizen Dave has it right. You use your free stuff to build a market such as the folks in the Renderosity Store, BBay, and a number of other sites linked here have done. It's like the free pretzels and peanuts (salty stuff) the bar tender puts out on the bar to get you to buy a drink. If you're in the business of 3D for business, be a businessman/woman/person/...

Gordon