Delayed consistency checking

Racer1

Why not do very basic consistency checking up front, and then have the rest validate in a separate thread after the user connects? An "Unverified" status could show up by the player name until their files are verified. This way, the default could be a full validation (similar to competitive servers), without the horrible load times.

The server could still decide how to handle invalid files (allow, warn, kick), but at least everyone playing (even on pub servers) would know if a player has modified anything. For servers that do decide to allow certain changes, it would be nice if players could determine which files had been changed.

CrushaK

File system access may cause noticeable hitches in game. As far as I know, UT2k4's anticheat mod AntiTCC (which was made by a single excellent coder from the community who always kept it up to date against whatever new insecurities hackers would try to exploit) had some midgame consistency checks in it's early versions, which caused somewhat of a love-hate relationship to the mod for many players. It's necessary but annoying. In later versions was the midgame checking disabled by default, since other security measures have been introduced since then that made it less crucial.

Racer1

A low-priority independent thread (no Lua) doing file access should not cause any hitching; although it might drop FPS somewhat for CPU-dependent games like NS2.

I would assume that the file checking would finish within the first 10-30 seconds of joining a server. It usually takes around 5-10 seconds to join a team and spawn in, and usually at least another 5 seconds to get to the fighting. So, I would think players would be somewhat forgiving if it wasn't a huge hit.