Well, a US court has ruled that first-sale doctrine applies to software.  This means you have the right to re-sell software you've purchased.  Where the issue remains muddied in relation to Stardock is whether or not the vendor is obligated to provide patches for that resold software.  I've already found myself in the situation where I purchased GalCiv II then wanted Dark Avatar but could only find the Gold Edition to buy.  So when I entered the Gold Edition's serial into my Stardock account I effectively "lost" a GalCiv II license.  I really would have liked to gift that one to a friend but a courteous e-mail exchange with Stardock left no doubt for the issue that they would not un-register the original serial so I could transfer it to another party.  Which is unfortunate as that party might have gone on themselves to purchase Dark Avatar and Twilight as I have.  After all, providing patches wise, every license was paid for (GalCiv II, and the Gold Edition) so Stardock actually ended up with one license less they already budgeted providing patches for.  See the link for the story!

Thank you Stardock for making great games.