https://support.steampowered.com/kb_article.php?ref=1327-WUJX-5722

vac secured game list : http://store.steampowered.com/search/?sort_by=Type&category1=998&category2=8

VAC and Game Ban enabled games can either be bought for your own account, or gifted immediately. They can no longer be saved to your inventory for trading purposes. If you directly gift a game to someone who gets permanently banned, you won’t be able to gift that game again.

How does this affect gifting?
When a user is caught cheating, their Steam account is banned from playing multi-player on secured servers. This creates an incentive for people who cheat to stockpile copies of games on one account and to gift them to low value accounts where they can continue cheating. In response to this problem, Steam no longer allows users to purchase copies of VAC or Game Ban enabled games to their inventory. Additionally, if an account has directly gifted a game to other players who have been VAC or permanently Game Banned, then that account will lose the ability to gift that game.
We’ve taken these steps to ensure the integrity of the multi-player experience for those participating in online gaming communities. We understand that the restrictions on buying to inventory may be inconvenient for some legitimate users, but we believe that these steps will reduce the number of cheaters you’ll play against. And that’s important in having an online gaming experience that’s fair and enjoyable for everyone.

as far i could understand you can no longer buy VAC enabled games as a gift :

1. CSGO ,CS:S ,CS
2. ARK: Survival Evolved
3. RUST
4. DAYZ
5. Left 4 Dead 1 & 2
6. Garrys Mod
7. All Call of Duty series
8. Squad, insurgency ,killing floor, grid2,dying light

Game Ban enabled games -

1.dead by daylight
2.mount blade warband
3.Rocket League
4. Arma 3

Game trading rip

Another change that directly hurts us..

However, I am not too worry yet. This change either does not improve the cheating situation or hurts Steam's profit. I guess some publishers would not want their games to be added to the VAC scheme in the future.

csgo not new its same since start of summer sale, cant buy as a gift. but for others still can buy to inventory (didnt complete purchase but probably will work). maybe they didnt activated yet, weird.

I belive its only for gifting.They did not mentioned anything about trading.

I think they will disable add gift to inventory button. But I don't know what will happened when he/she decline gift :)

)

But even if You choose to "send directly to user" game will be added to Your inventory (it will appear as addressed gift) - it's mean that they will probably rebuild the gifting system if they plan to give an option to send the games a.k.a. "gifting them immediately"

Ok we know what happened now. I sent a gift to my friend and he reject gift and gift in my inventory now. I've tried second time on same game and have 2 same game in my inventory. I can send another person in any time. (Didnt try but I think you can manage gift and return gift to your inventory before friend accept or decline gift.) and Gift have "not tradable" tag but there is no any date for tradable. I dont know gift will be tradable or not. So, as there is no problem for the person who purchased the game, but resellers fucked up on theese games :(

I forget one thing, he cant add gift to inventory.

Yes that is correct.