I read this on another website a few months ago. And it has helped our clan catching those hacking on our server.
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I have never failed to figure out who was using the commander hack on our server or any other server I have been on. First, look at the cars that are dropping... if they are from your side and you can see them on the radar, chances are he is cheating from your side. If it is the enemy have someone on the other side do the following or suicide and switch. Go into specator mode. Switch from player to player looking for people that are not moving or are in random parts of the map doing nothing (in buldings away from any action, in bunkers, etc.). You can also start by looking on the map for teammates that are away from the action. The real noobs act like a dedicated commander when they are in the hack console.
If you don't find an obvious one, keep cycling through players and watch for players that stop suddenly (gun is sometimes pointed in weird directions) and then cars, crates or arty starts and they start moving again. In general, if you know how a stationary or active commander behaves, you won't have any problem isolating the person.
He may even give himself away by bragging or being a smacktard in the chat. A few times I have looked at the scores for someone who isn't scoring or getting killed much. Again, they tend to be into the cheats and disrupting a game than actively trying to get the gold medal. BF2CC will tell you how long they have been on. Note, kills and TKs from arty are credited to the REAL commander, NOT the cheater. I have been commander when the cheater took over and I was accused of the TKs from constant arty on our base. Death by cartillary or falling crates is "xxx is no more".
Don't give away the fact that you are looking for him with chat messages accusing players or pausing the game. The more active they are with the cheats, the easier it will be to find him. If you scare them and they leave, you won't know who was doing it.
You should be able to eliminate fellow clan/club members and regulars. A lot of the morons wear clan tags of known cheating sites like MDK, 187ci, etc. Just be patient. Once you find him, try PB screenshots, Fraps, or screenshots and ban him so you get hash, IP and other info for filling out a report
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Hope this helps.