sounds like people are getting pissed off with pb kicking them for md5 tool problems and have overidden the file to stop getting kicked. if that's the case i don't blame them i get kicked for it and i wished i could change that too. although i do not know what the md5 file does, so i don't know if they are doing it to cheat, or just to stop being kicked all the time.
systemcfgoverride.cfg is used to override the standard system.cfg (which cannot usually be changed as it is rewritten when you exit the game) it can be used for custom graphic settings keybinds ubilogin cl_netstat r_displayinfo cl_cmdrate cl_updaterate etc it's intended use is so as that low spec machines (like Unreals) can be fined tuned to play well on any server. all normal settings can be set to low and then those that are checked set indiviually. this can lead to players with high spec machines running special configs for max framrate (like Hanz, Scarab313, me, err oops ;D) since xt v3 most pb servers kick for this but not all ;D my personal opinion is that ACC are hypocrites as they allow a caught cheater to play on their server "because he's a nice guy and didn't mean it" but that's another story