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

if we trade (not gifting) games with someone who gets banned, are we still be able to gift/trade games right? valve doesnt talk about trading

" If you directly gift a game to someone who gets permanently banned, you won’t be able to gift that game again."

looks like arma 3 added to the list in game ban enabled games, cannot buy in inventory anymore

Actually You can - just choose "send to friend (Your alt)" and decline it. Game will appear in Your inventory. It will be untradable but You can send it directly to someone who will add it to his library. The most important question is : if buying games (more than one copy per one steam account) during sales is safe? What will happen with all my X game copies when one of the recipients (X game) receives a VAC?

God, I now realize how monumentally stupid my post was. Shall delete it now to avoid further embarrassment. :D

I can see option now save to inventory despite being vac enable or have anti-cheat though the message is still there. Did something changed again? This is odd as it contradicts the message not being able to save to inventory but the option is there when you attempt to checkout.

STEAM GIFTING CHANGES (4 May 2017)

Source: http://steamcommunity.com/games/593110/announcements/detail/1301948399254001159

Today we’re announcing changes to gifts on Steam. The gifting process has had a bunch of friction in it for a while, and we want to make it easier for you to share the games you love with friends. Steam Gifting will now be a system of direct exchange from gift buyer to gift receiver, and we will be retiring the Gift to E-mail and Gift to Inventory options. Here's a quick breakdown of benefits from the new system:

Scheduling Gifts Is Even More Straightforward
Go ahead and buy a gift months in advance and have it delivered to a friend on time, every time.

Declined Gifts Resolve The Way They Should
In the old system, a declined gift would sneak back into the giver's inventory and remain on their bill. Now, if a recipient already has the title, or just doesn't want it, they can click decline and the purchase is refunded directly to the gift giver.

Safe Cross-Country Gifting
No more worrying if a Gift to E-mail or Gift to Inventory is going to work for a friend, gifts sent through the new system will always work on the receiver's account. When there is a large difference in pricing between countries, gifting won't be available and you'll know before purchase.

These changes are now available. Please let us know if you see any issues or have any feedback.

Note: Pre-existing gifts will be unaffected by this change.