I dont think banning GPL would be the solution.... however i think better notification could be of the license could be employed e.g. set the listing areas, to have a ajax based update after you click 'ok' or 'accept'. similar to how many sites protect adult/mature content, by having a 3 dropdown lists for year month and date, the user must use to access the content. At least then the cargo cultist's out there would realise that there was something different about the license, and there just idiots if they ignore something between a <h1> which says something to this 'GPL code, do not use with proprietary code bases' just my 2p's worth