Stupid question, but if somebody posts something as being "Unrestricted", what are the limitations of this as far as site TOS\ettiquette go if you cannot contact the original author to ask thier permission\they don't answer either way when you ask.

Obviously, it would be wrong to simply to grabe something and to resitstribute it wholesale, or to try tosell it as your own work.

For example, could you grab a small amount of geometry and re uses it in your own freebie. Such as taking the knob off of a radio and using it on an oven model, or re using a door handle?

Is there a rules page laying out exactly hwat you can\cannot do?

It goes without saying that you'd want to give credit and back link to the original model.