On a recent LHR-LAX flight with Air New Zealand I suffered the passenger from hell. Little brat in the row ahead without a word just leant over and closed my blind! This blind was right next to me, not even spanning little brats seat, I opened it again where upon Mother brat rounded on me as little brat didn't have enough darkness to watch her computer game.
If we'd have had a pleasant discussion about it first I'm sure we could have worked something out. Unfortunately civility seems to be a lost quality to most people and little brat missed some of the best views of Greenland, Canada and the Rockies that I've seen for some time.
My worst experience of this 'closed metal tube' problem was a lunch time flight with Delta LHR-DTW. Before we even pushed back at LHR, the Delta Police systematically went down the plane closing all of the blinds. A few protests ensured but Delta Police insisted it was a security requirement. Guess which US airline I never fly with now.
Generally I don't have many problems with the window blinds and it just seems to be the occasional paranoid crew or passenger who know their rights.