I don't think doing such a thing will stop the trust farming by DT1 members. As long as you can gain positive trust by adding someone to your trust network, it will be abused.
Haha, you are right, Vod! Abusers always find their new approach, new stragegy to abuse systems, including trust, rank, merit. Adjusted current systems more, they will adapted to change and keep abusing new updated systems. That's the fact, something like natural selection process.
However, with stricter rules updated and integrated to current system, abusers have to changed somehow and I believe they will be changed somehow to be better ones (part of them will change to be real good users in the forum, just my hope).