4. When accepting your application I will give you neutral trust.
5. In case of violation of above rules I will give you negative trust.
That is not what the trust system is intended to do. Why would you give them a neutral trust for just accepting their request? That indeed looks like trust farming and your negative wouldn't be justified since you can't go around tagging members for not following your rules. That's an untrustworthy behavior for me and I shall not trust your ratings.
Also, what defines reputaed members on bitcointalk for you?
From forum rules / Trust => Risked BTC amount is money that the person could have stolen or did steal.
If I understand correctly I can mark a risky transaction by giving neutral trust - as side effect other lenders will know about my loan.
The second action of giving negative trust in case of fraud - which is the actual act of not repaying the loan - is also an intended trust behaviour.
I never used the trust system so am open to directions from seasoned member, but it looks apropriate for me to use it the way I described my intents of using it.
About reputable members -> as a general rule I would consider a reputable member anyone who managed to survive being at least Sr.Member without negative trust.