In reply to Miroslav Glavic.

Nothing stops you from doing that. That was the fear in the early days of companies offering GPL licensed products. People would pay for them, get their money back then redistribute or use the product anyways. It turns out that fear has not been realized. There are far more good customers that outweigh the bad. I think themes get the most refund requests because no matter how good a theme demo is, the only way to know for sure is to obtain the product and use it for a few days.