Delete giveaway - how much setback?

So then you aren't as heavily punished as I imagined, thank you so much! You are right about the numbers, I can currently host 10 gws with 23 gws marked as received.

Just one correction, when you create the giveaway you get the -1 slot, not when you delete it, deleting just means the user will not be able to give recieved feedback to get it back

I believe the consequences are the same as when the giveaway is deleted.
You lose 1 slot and that's it.
Also when you hover your mouse over your gifts sent you will see 1 red marked X with not received, but if that doesn't annoy you that's pretty much it.
Someone can correct me if I am wrong of course.
You can also try to provide another key later on, if you can contact the winner and they can mark it as received(even if some times passes).

Sadly sometimes you aren't allowed to delete giveaways, but it doesn't affect you much. The worst what can happen is people will look at you as at worse gifter, but its not like you attempted to scam. I have two unrecieved - once I set wrong region restrictions, because store had different regions marked than it actually had and other time I made giveaway for game which had same name as other one and I picked wrong one.
I think sgtools maybe can set a restrictions against people who delivered games? Also you lose one giveaway slot. The worst to me probably was loosing a good name when I haven't got aprovement to deletion.
Also some groups don't want to accept members who don't deliver gifts.