We have an Out of Sync counter and we can also see all players rec games as far back as their first games. We have already started to ban players with very high OOS % rates, and maintain this on a daily basis.
Recently a player named "Found" was abusing OOS to gain ranking. We have dropped his rank from 2500 down to 2100 as a warning, with a second strike as a Ban and IP ban. And will be watching him and others that try this closely. The sad part of this is that Found is a really strong player and from watching some of his replays he is one of the best in the game. Perhaps without cheating he can bring his rating back up and prove himself once again.