Shared Lounge, Trading Section, General Chat,Wow Scams help, age of conan section, suggestions, graphics section
These are the places I have found that I cannot rep someone at. It gets tiring looking through every post they have and seeing that I cannot actually give them reputation.
This is for Corsix who made an awesome machinima who I think deserved rep for it because it was cool to share with the community, (the Blind machinima was also cool even though it's not his.)
All in all, I can understand you do not want reputation to be gained for certain sections but trading section I don't quite understand. People who are legitimate should be able to rep the other person for being a non-scammer and posting on their thread saying they're legit and won't scam you.
Suggestions to my suggestion can be made if need be.