how does steam handle duplicates? does it only redeem the ones you don't and leave the rest in the code like gog? or does it spawn off a gift code for what you can't use? or is it just wasted?

if its either of the first 2 it seems like it should be fine(in that case I'd guess the question would be what to do with the extra, return to sender for redistribution or give away yourself or whatever?(but since that isn't what you asked I assume its the third. in that case that seems kind of a dick thing for steam to do when it'd be easy enough to have it check what you already had))

I guess you could enter now and remove yourself if he replies to the negative or maybe would that be bad manners?

(not an answer obviously since I'm clearly not moneyhypemike, its just never come up in my experience and this way if he replies it'll be easier for me to find the answer by looking for this comment)

I'd like to know as well. D: I own Civ V and G&K, but nothing else.