How does Team Fortress 2 rewards avoid cheating of hats and weapons? Does their master server give the player the items? Since the community can host their own servers, what stops someone from hacking the server and making them give out any reward to a player on that server? The only logical reason is that it is centrally controlled by Valve and the profile must be stored online. Otherwise you could hack the profile and add any items you want to it. This seems to work with a time based system, but what about a game where you unlock things by doing something. Like finding X amount of something unlocks Y. How would you avoid the server admin cheating and giving out items in this scenario if you have central profile server?