In general we very much do like the idea of giving back to the developers. We believe that this is already happening. A lot of users let us know that they use the free downloads at GPLDL to try something out. Most of them get a license frm the original developer once they enter a productive state that generates some revenues and allows them to pay for a license.
We also encourage anyone to get a license as soon as possible to support the developer and benefit from the support that the developers provide.
It is important to note that GPLDL has not been set up to harm the developers or encourage free riders but to allow people to get something started which they would or could not do if they had to pay for expensive support licenses right away.