Of course we all want folks to buy Kendo (to support further development) but even as someone with a licence to the product (as part of my Ultimate Collection) I am often prevented from using KendoUI with clients by the licensing confusion that is the GPL.
My clients understand that t is covered by my commercial license to code for them, and they can use it royalty free. The problem is int he future and ongoing compliance. What they absolutely do not want is to have to make sure any dev who will ever touch that code in the future is ALSO a telerik licensee. It is simply too much to keep track of for a UI toolkit.
You will sell more copies and greatly improve the ability of your evangelists to get Kendo into the market if you move to a significantly more client friendly license.