You're right, but you forgot one thing.
First, it checks if the xuid is banned, and then if the xuid is clean. (Unclean means that the person has made a modification to his mw2 install, which is mostly a hack (it gives also the reason of the tempban)).
The last part is (afaik) the same as stated by you.
Ah, I missed that. I do see it in the source code.
I would assume this would be built in... after all what is a master ban list good for?, but seems b3 is needed for this..
Oh Well...
TBQH, I think i will ask the creator if I can re-release that plugin with some enhancements...
1) I want to build the aimbot detector into it (don't ask why, I just do)
2) I want to move the kick message to the .xml
3) I want to cache bans... meaning instead of always querying the master server, I want it to download a copy and then re-update every x minutes...
4) option to turn off kick for heartbeats (since game does this with steam auth error)
5) Full control of kick and ban and tempban for violations.
I also want to mod the plugin for use with PBBans (for other games), GCC, AON, etc..