I bought a region free key from Kinguin, but after activating it, I see it ends with "(RU)", after the game name.
Does it means it's region locked for Russia? May I get banned on Steam for only activating without playing? What if I remove this game permanently from my library?
The seller keeps saying it's a region free key, but then why would it shows "RU"?
Steam has a good outline of their policies regarding regions.
When redeeming a key, if there are any issues with the key and your current region, Steam would not allow you to activate.
The primary thing to note is attempts to bypass restrictions (using a VPN for example) will result in a ban. However, this is only if you deliberately try to bypass their limitations. If you have activated a product, and it is successful, and you are able to play it without doing anything weird to bypass their restrictions, they basically don't care at that point.
Of course, Steam is free to modify their policy, but they have yet to remove already activated game due to "region" or even "legal" issues. For example, they are no longer able to sell the game Alpha Protocol due to licensing for the music expiring, so nobody can buy it anymore, but this game still remains in my library, and I am free to download it anytime and play it.
The "Region Locking" with Steam primarily has to do with pricing. The price variance is HUGE. For Skyrim, it is priced at only $6.45 USD equivalent in Argentine Peso, but a whopping $52.60 USD equivalent in Israeli New Shekel. Their region locking is to prevent you from buying everything using the "version" with the lowest price.
Beyond that, some countries will ban certain games due to various reason such as politics, ratings, licensing, and so on.
If you were successful in activating the key, and you are able to launch the game, the key was not region locked. If it was region locked and you were outside of the region, Steam would have warned you that you are activating a region locked key, and then you would only be able to play the game in the regions to which it is locked.
On the topic of region locked games, you will not be banned or penalized in any way for playing a region locked game, provided you are not using a VPN to bypass said region lock. If you attempt to launch the game while not in the region, it just won't work. If you do use a VPN to bypass the region lock and Valve detects it, you will be banned.
I'd say that the RU indicates a Russian version of the game, i.e. possible censoring or alterations of content to fit with Russian law.
TLDR: Don't use a VPN to play the game and you'll be fine.
