I understand the DT system to work with trust and reputation of a user in the forum that makes other DT members to include them in their trust list and even though some users earn trust due to the assessment of their past behaviors to their present but i think that an inactive DT member should be removed because if a member can stay out of the forum for over 5 years, what will be the probability that they will come back to the forum someday and still maintain same level of reputation that got them trust from some DT members? Perhaps, for those who made it clear they won't return to the forum again, what is the essence of still leaving them in the DT? besides, the positive trust feedback from other DT members should be enough.
Why don't we wait till their reputation is tarnished before vetting judgement. Besides it wasn't their activeness that earned them the trust from other DT members so being active or inactive doesn't mean anything as long as they maintain their clean reputation whenever they choose to become active again and the nature of their activities and post remains consistent with what it has always been before they left leaving us with no doubt about the identity behind the account.