I'm not sure about subtracting exclusions.
I'm not sure what you mean by this. So, if Claire was excluded by 3 DT1 members, and included by only two she would remain on DT2?
What I would be fine with is if there were two instead of one inclusion by DT1 to be DT2, I think it would reinforce confidence, and at the same time reduce the number of DT2 that I see it a bit long.
I agree, there should be at least two DT1 inclusions at the very least.
Perhaps this should be a customizable option for users to set.
It is customizable,
as you very well know.
I generally agree that in order for someone to be excluded from your trust network, there should be a strong consensus that the person should not be in your trust network, so a maximum of net 0 is appropriate for someone to be included (assuming one inclusion). I also don't think that having a limited number of "bad" people in your trust network is not the end of the world, especially if this person is not regularly sending trust ratings.
I'm not talking about my network, I'm talking about Default Trust. You obviously know that the Trust System is customizable, or you wouldn't have customized your own. This wouldn't change anything for those of us who've customized our trust lists, it would only have effect on those who have not customized there's, i.e. newbies and those who've yet to bother.
Here's an example of why I think this is worth discussing; I recently included a member into my trust list who's not very active but has been here for a significant amount of time, and seems to have a good head on his shoulders. He came to my attention when he questioned me about a tag I left for a suspected scammer, suggesting that I may have jumped the gun. His concern was admirable, and showed restraint. I've had the same concerns in other situations. After looking through the reviews he left for others, and reading some of his posts I decided I wanted to see his reviews in my custom trust system.
Since I'm on DT1, now that I've added him he's on DT2. My actions have an affect of the trust lists of the majority of forum users. I don't believe that I alone should have that power. If some other DT1 member feels the same way about said user, then great, I'm not alone.
Also, if Bob believes he should have that power, that would Bob specifically the type of person that I say shouldn't have it.