giveaway marked as received yet still in inventory

check if he's tryng to trade it, I got 1 winner of mine that I caught trying to trade what he won

for wanderlust, wait 2 more days and if its still in your inventory cancel the sending and ask for a reroll(make sure to cancel sending it to him first)

Remove the user's name from your post, or you may be hit for calling out.

If it hasn't been 7 days since the giveaway ended, you can try contacting the winners and politely remind them to activate the gifts. If after 7 days nothing is done, the gifted copy still in your inventory can be pulled back and re-rolled, and the traded one can be reported for not activating.

Entice them to play with you. I'm much more amenable when my friends are in the line of fire with me.
I'd talk to them. Make sure they want it, don't have it, and will activate and mark received.

I've never understood this, as soon as I've given the gift I don't give a shit what the winner does with it as long as they mark it received. After it leaves my hands it's no longer my property. I'll tell you something else as well, I've never been the kinda sad anal loser who checks other people's accounts to make sure they follow the rules, and if not scramble to report them. But hey that's just me, flame away or feel free to run and tell teacher I'm a bad boy.

Once I marked as received with the game still in my inventory because, well, I'm a fan of mass activations (meaning activating a lot of games at once) and I was planning to activate 50 games at once the following day (already scheduled it and the gifter knew about it. I only marked it as received so the gifter wouldn't have to deal with the blue bar and I wouldn't have to deal with the green bar, but in a few hours, I was already suspended. I spoke to CG after what happened and he said that it was ok to do this as long as I activated the game within the 7 day period, and that no action should have been taken until after the week was over (it had been a little over a day at that point, I think, but only 2 days or so after the giveaway actually ended, leaving me 5 days to activate). He reversed the suspension, but since then I've been warning people who mark the game as received earlier (some people mark it as received as soon as they win to hide the bar, especially when they know the gifter and are confident that they'll receive the game) so they don't have the same problem that I did, even if it shouldn't actually be a problem.

tl;dr: They have a week to activate the win, don't stress over it until after the week passes, because you may not know the full circumstances.

PS: I actually do see quite a few people trading wins on ST because I'm an active trader, so take a look at steamtrades and the SPUF trading forum just to double check, if you don't see him trading it atm, I wouldn't worry for now ^^

I would say wait a bit more and if still in inven by the end of the week, reroll and cancel the gifting.