Go find some of UHU's posts... you will see that he clearly does not want links to his site.
He lets out his designs for a limited time only. Then people start trading them and upping them to hosting sites, distributing them like they own the files. To stop that he removed all his models and shut down his site.
Same thing happened to Trotskiy's planes. Same thing happened to Ojimak's planes when someone built them a different livery. Same thing happened at Metmania except the files were being sold online.
The thing is, you release anything on the internet and you really should just accept that anything will happen. When you start making rules about how your files are to be treated, the LEAST one should do is respect those rules as payment for the model's download. Nothing is actually free.