Game region lock question Witcher 3

The different SubIDs for different regions thing is slowly becoming the thing of the past - Valve introduced a new type of region lock several months ago, and the majority of new games use that one instead of the "old" one. As a result, games are less likely to have a visible RU tag. So you should always check SteamDB for locks instead of relying on tags.

Things become even more complicated because of games being locked retroactively quite often. If a preorder gets locked upon release, all its inventory copies become locked, it will be impossible to activate them outside of the region of purchase. However, if the publisher does not add the "play lock" (onlyallowrunincountries on SteamDB), already activated copies will remain playable.

Now, Witcher 3. Its steam page was modified several times, so whether or not you should be worried depends on when and where it was purchased. It's possible to check the exact SubID of the game's inventory copy - see if there's a risk of it getting a "play lock". If there's a risk, better trade it to someone in the region where it was purchased. If there's little risk, better activate it in case they apply a retroactive "activation lock" soon.