Was this a general question, or are you interested in particular examples?
A general question. There's discussion about this between the Dutch sysops. One person has unblocked some addresses, I have done the same before. Others get angry about that because we did not discuss our action with the sysop who did the blocking before we unblocked. They say it shows that we distrust the sysop who did the blocking
Same old same old. We have had the discussion many times before :(
Waerth/Walter