DT members aren't obliged to 'be always active' in any form or way. Most feedback is left with a valid reason and shouldn't need to be revised that often either.
It seems to me that questions around DT member activity revolve around what theymos said in this below-attached post regarding his tweaking of the DT1 list criteria on about a monthly basis, which seems to have some activity criteria.. sure it is not "always" active, but requires being on line and posting as I bolded those two lines, below:
#3
I will periodically (maybe every month) be reconstructing the default trust list to include everyone who matches these criteria:
- If rank was determined solely using earned merit, then you must be of at least Member rank.
- You must have been online sometime within the last 3 days.
- Your trust list must include at least 10 users, not including ~distrust entries.
- You must not be banned or manually blacklisted from selection.
- You must have posted sometime within the last 30 days.
- You must have at least 10 people directly trusting you each with an earned merit of at least 10, not including merit you yourself sent. These "votes" are limited.
- You must have at least 2 people directly trusting you with an earned merit of at least 250, not including merit you yourself sent. These "votes" are limited.
..........