Can I check if a Steam key is valid without activating it?

Rofl

yes some days ban

Yeah, probably a ban for 2 weeks or 1 month.

yes some days ban

That's for Steam gifts. If you paste a gift link in as a "key" it will automatically be detected.

I recommend simply using the key yourself since you don't have the game anyway or simply give the key to a person on your friends list that might be looking for FTL. Simply check on the game tab and see who has it on their wishlist. If it turns out to be used then at least you will not be flagged down here...I think that's the best solution without risks.

I don't know if it's possible at all, if it is then you would have to wait prolly 2 months for an answer sadly :( They said they will focus more on their Steam Support in the nearly future, i really i hope they'll empolye one or more ppl there. :D

Right, I mean a second key...tremorgames.com doesn't cost you real money, just some time earning coins. But, they have to have the game, and it depends on the game how many coins that would take. Anyways, just an idea.