chandra: If you don't check the "save this card for later use", the card info is not saved. We never store card details directly in our database.
Worth noting that an option to check and remove the card number is at the top of your
order history.
A bit of clarification would be nice, as it would seem you just contradicted yourself(while also providing some good info about checking to save this card as saving the info).
You said the card info is not stored in your database after saying(basically) that checking save this card saves the info somewhere(I would assume you guys/gals don't let just anyone save the info and that the servers doing such/holding such data are at least partially under your control). This means that if you check to save the card info then GOG DOES in fact store your info(even if on another server) if you choose for it to be saved.
The distinction is moot(imo), however, as to who holds the data if someone gains access to your account and such has been saved to it. Either way(whether GOG stores the data or someone else) if it's saved and someone accesses your account they can buy games with it.
paladin181: Good to know! I'll stop saying GOG doesn't store payment info. That used to be the case but is obviously not now.
HunchBluntley: Read
immi101's post above. He summarizes pretty well how it works.
That info is good to know, but it says the data is only reverified if one hasn;t used it in awhile. This means that if someone buys often enough and someone gains access to an account with saved payment data they can possibly buy games with it. Also even if the data is a token/encrypted if the before mentioned circumstances occur other people can still buy games with it to resell/use themselves if they have access to your account.