HereForTheBeer: Technically you could. Not sure about the to-the-letter legality with regards to the EULA or buyer / member agreement. Just had a thread a couple days ago with a similar discussion.
Lexor: If you think about
this, then OP's situation is quite different. It is perfectly legal to buy a gift then use it to download the game, burn on CD/DVD then treating this as a present.
Seems that the person redeeming the gift code becomes the owner of the license, and the OP would need to be the one to redeem the gift code to accomplish the transfer to a disk. That would means he then owns the license and would not be able to give the game to his cousin. Where it becomes similar is that the OP either needs to:
A) have his cousin redeem the code, and the OP then logs onto the cousin's account to obtain the file for burning to a CD. In this case, two people are using the game license (even though the OP might never install it). This is the parallel to the other thread, logging into another's account to obtain the installer. Though only difference is the purpose for doing so.
B) use the gift code himself, which puts the game in the OPs account for future downloads, and then burn the installation file for the cousin. In this case, the cousin doesn't actually own the game license.
C) also buy the game, so both of them have the license and then its only a matter of sending a file. The OP didn't state whether or not he already owns the title.
If he does, then I think it shouldn't be any problem whatsoever.
I'm not arguing against doing something like this to gift a friend; frankly, I think it's perfectly
reasonable from a legal standpoint since the cousin gets the game and GOG gets the sale, so long as the OP doesn't keep a copy for himself without buying the license. The problem is that it's assumed that people will not do the right thing. Billions of individual sales annually should argue against that point, but that's where we find ourselves.
What's interesting to me is that the cousin is paranoid about downloading a file that at least several thousand have already done, and then worrying about what harm it will do, but has no problem giving out his login info.