I just changed to DT3 to check something, and I see some users have (0) beside their name... yet they are still on that trust level, and I see their trust as "trusted"?
An example would be user Hesaplar.
Hesaplar is excluded from Blazrs (DT2) trustlist, but included in the one from EAL (DT2 aswell).
This makes their weight on DT3 (0), which however still means that their feedbacks are considered as trusted.
To not see them, another exclude from dt2 or higher would be needed.
tl;dr: (0) means one include and one exclude, while (1) is an include only.