Practically ALWAYS when you play online in the cod mw 2 there is a hacker who has UAV and AUTOMATIC SHOOT, there is no way to get fun playing with that people using those cheats, please add the report option as the mw3 in order to stop them.
And other thing, sometimes when you start a online match, the system doesn't search the enough players to start the match and like there is not any limit of time, the match never starts, so please add a limit of time even with few players to start the game.