We've recently found out that someone is
selling copies of our game on eBay. Since the game is Free Software, we naturally have nothing against someone charging a fee for distributing it. Instead, our concern is that this particular vendor does so in a misleading manner, without stating that the game is a development version, full of bugs and missing many of the features listed on the vendor's page, and that it can be acquired free of cost online. We are worried that this behavior may lead to dissatisfied buyers and ultimately damage the reputation of our project.
For this reason, we have discussed adding an attribution clause to our CC-BY-SA 3.0 licensed artwork in the game that requires a seller to make any buyers aware that the game can be downloaded for free from our website prior to the purchase.
To the best of my knowledge CC-BY-SA 3.0 affords us the ability to add such a clause, and to the best of my knowledge CC-BY-SA 3.0 is compatible with the DFSG.
I would like to ask whether you all agree that adding such a clause to a Debian package would be compatible with the DFSG and other relevant guidelines?
Thank you.