So, to combat cheating all you have to do is:
- Run a 3rd party program on the gamers machine that only allows "allowed" executables to run.
- Take random screenshots on the gamers machine, and have somebody look at them.
This is not exactly rocket science software.
Who wants to write another one, where we can upload the pictures to wherever we please?
Screenshots:
Not all users run the same hardware and you can have screenshots failing because of that. Case in point being Punkbuster + SLI. Oh, and there are hacks that can block PB screenshots. We have one on Crysis Wars.
Processes:
You will need to know exactly what apps to scan for, unless you create something that scans for memory hacks in general, which can lead to issues with with non-cheating apps as well.
I see X-Ray bans by:
GUID - As easy as creating a new account with Gamespy
CD-Key - Generator anyone?
SteamId - Steam pools?
(I'd prefer hardware ID bans)
And then we have not touched on the subject of client file and cvar changes.