I've seen a few discussions over the years regarding the potential for someone to steal your idea if you open the sources to it. (One such discussion was held on HaD last night actually). I can understand the issue if you want to coin from your project. If you are developing code or hardware for an industry, lets say a gamma ray carbon dust detector to be used in mines, then I agree that it might be safer towards your pocket to keep the sources for yourself.
But for 99.9% of my designs, including the PoolButler, I rather want to develop something that no one has to steal to recreate, but rather just open the HaD project site, go to Github, do some reading and recreate (and potentially improve) my project. My project will however carry GPLv3 as I do not wish for someone else to "steal" my project for commercial purpouses. If you do however want to produce kits to sell to those that cannot program AVR's, do not have access to laser cutters and can not wield a soldering iron, please contact me first. I'm okay with someone selling kits if the price only includes the raw material and the work you put into it, not any other bloat for "your idea".
So expect open designs being posted in the next couple of weeks :D