Rockstar are taking a stern stance with Max Payne 3 multiplayer cheaters and have now taken steps to quarantine confirmed cheaters.
Any players using hacked saves, modded games, or other exploits are being singled out and pooled together in a dedicated cheater pool. Cheaters will find themselves in empty lobbies or always matched with games full of other cheaters. Players in the Cheater Pool will also have their scores omitted from the legit leaderboards.
Rockstar promised this in June and asked players playing on all platforms to send any knowledge of cheaters to email@example.com.
Those that believe that they have been wrongly placed into the cheater pool can also email Rockstar with the mentioned adress, along with your Social Club Nickname, Gamertag, or PSN ID along and a detailed explanation for why you think you might have been placed in the pool.