I'm going to copy and paste a response I just wrote about smurfing and what we are doing against it.
Two factor is a double-edged sword. When talking about smurfs, usually smurfs are higher engaged players that are familiar with VALORANT(which makes sense, they are good enough to smurf and make an impact). While two-factor can reduce smurfs, it's not a silver bullet, this is especially true for smurfs that are willing to spend money to smurf; which usually higher engaged players are willing to spend money so they fall into a group more likely to. It becomes a numbers game of what is acceptable and how much of an impact are players facing when encountering a smurf.
These numbers are made up, but lets say 1 in 10 games a player encounters a smurf between Iron to Silver and decreases as you climb ranks. Lets say with, after researching, we find out that two-factor authentication would probably reduce that to 1 in 15 games for these players, reducing smurfs by 50%. We would be reducing smurfs from 1% to 0.5% of concurrent users. In return, we also research and find out lower ranked players are less likely to have money, less likely to own their own cell phone, or happen to use a local PC Bang in order to play Valorant. By enabling two factor we figure that 3% of players would no longer be able to access ranked nor have the money to solve their access to ranked. We have to decide if that is worth the cost, when it won't stop a smurf who is willing to pay the money to get around the system. Then on top of this we have to add the work of upkeeping, monitoring for exploits, and fixing any issues with various service providers to upkeep the system. So we would essentially be letting a 1 in 10 game occurrence completely block access to a large group of players, and we'd have to ensure that we could effectively keep fighting work around to the SMS verification and that slowly overtime smurfs would build up more accounts(just like they have now) with access to ranked and slowly more and more smurfs would get around this system. When you put SMS verification up you aren't putting up a barrier to prevent smurfs, you are putting up a paywall essentially.
Now we view this as not solving the problem for what it is, and just creating a secondary solution that blocks people from playing the game because we can't solve the problem directly. This is a mitigation not a solution. In reality, if we had a good match maker that could detect smurfs and correct their MMR, we wouldn't have to rely on secondary solutions that don't tackle the motivation or problem directly. SMS verification does not solve the reason why players are smurfing, nor does it correct a smurf account once it's been detected. It's an attempt to put up a wall and is just a barrier that smurfs can find a way around but ends up blocking more players then smurfs. Is there use cases for SMS, yes 100%. Would it be an effective mitigation, well yes there is a good chance that it would and it may even be worth it. Do we have the resources right now to implement it, know how it would impact the player base, and be able to upkeep it? Unfortunately no, and that's why we haven't gone this route. We just don't think we've exhausted all our attempts at solutions and need to fall back to mitigations yet.
I think a lot of it is also we don't want to be completely transparent with how we are tackling smurfing. We don't want smurfs to know how we have changed our MMR detection, how we are getting better at tracking them, and how they may be able to get around our systems. We do let the community know when we've made changes to tackle smurfs, but we don't exactly say what those are. In a perfect world it takes a long time to get an account rank ready(which it does now), then if you go into rank and start "playing like a smurf" you're MMR gets fixed very quickly. In fact, if you talk to smurfs(which we have), they are very aware that we do move their MMR very quick when they start to play like a smurf. Again this is reinforced by our research that shows smurfs are less common then players think, and remember we can ban off hardware ID which means we have a good idea of each PC and how many accounts that PC has.
All this means is that we have implemented the obvious solutions, which is tackling the motivations of why players smurf most often "I want to play ranked with my friend" - which we agree our ranked system isn't good for that; this led to the 5 stack solution. After making sure we tried to help reduce the motivations players had to smurf, now we are trying to tackle how fast we can get a smurf to their correct MMR so they don't disrupt games below their skill level. Unfortunately this isn't a super fast process and we won't make decisions to block players from ranked without it being a last resort. It's not because we want players to smurf, or it's good for our game, we are doing things it's just not always 100% obvious what we are doing to prevent and combat smurfs. I hope this paints a better picture of how we approach it!
(I also want to point out we just started testing new smurf detection systems in North America that are looking very promising and is 1 of a few new solutions we've been working on but again these all take a lot of time and validation that we don't break match making)
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