To collect the data, I picked 3045 of the newest accounts on the NA server on October 2nd, 2014 and scanned their 10 most recent games on two occasions (nights of October 2nd and 3rd). In total, I got around 27,000 games for these players. Out of these 3045 players, 2814 players had at least one game on their record.
While I can only present circumstantial evidence, the number of suspicious accounts is staggering. I will now try to present my finding.
1. Favourite game type:
|Game type (translated)||Popularity|
|Custom Dominion game||65.43%|
|Summoners' Rift bot game||22.37%|
|Summoners' Rift blind pick||4.60%|
This is the summary for the 4 most played game type for these 3045 players. While the tutorial and the SR games are hardly surprising, do note that the majority of these new players seem to prefer custom dominion games. There were only a very small amount of matched dominion games.
2. Custom Dominion games
The custom dominion games are usually less than 10 minutes short. Among these, it can be easily seen that most of these players are merely AFK in the game. In fact, around 85% of the players in custom dominion games dealt 0 damage in the entire game. This means that in the entire game, the player did not autoattack any other players or lane minions. They do not buy any items either. As far as I can tell, these players were simply AFK in the game for around 6-10 minutes until the game is over, then immediately hop onto another game. Out of the aforementioned 2814 players, 1450 players exhibited this suspicious behaviour at least 5 times. I believe around 50% of the new accounts are being botted using custom dominion games.
3. Non-custom games.
Putting custom games aside, there are 899 players who have played at least one matched game. In these matched games, only 19 players have played at least two games and dealt no damage (i.e. they probably afked two games). Since it's possible that these players simply disconnected from the start of the game, I will employ a slightly different method to assess how "involved" these players are.
First, I picked out players who have played at least one game of Azir, Cassiopeia, Skarner, Kog'Maw, Leona, Shyvana, Varus, or Ryze. Note that all of these champions have at least one very easy way to deal magic damage, but they cannot deal magic damage without using a skill (i.e. not Thresh/Kha'zix/Diana). Out of the 899 players above, 229 of them have played at least 2 games with the champions listed above. Out of these 229, 13 of them played at least 2 games which the player dealt physical damage, but not magical damage. Remember this include magic damage against minions and monsters. It is very odd that a player will deal zero magic damage against champions or minions in an entire game using those champions.
Different from custom games, matched games have LeaverBuster so the player has to perform actions in order to get not kicked out of the game. I believe it is likely that these players are employing bots which only autoattacks/capture points (see the video below, for example).