I think you're correct Tightslot, you can't win.
The particular incident that I was part of that makes me suggest the possibility was on a daylight transatlantic flight when a crew member reached from the aisle, past me to the window (using a tray as a reach extender) and closed the blind by my seat. No "excuse me", no "would you please" and, from memory, no previous annoucment on the PA. The reaction when I immediately reopened the blind was like a schoolchild who had been caught. Why would you close the blinds on a daylight flight at a time when everyone was wide awake and then (as that crew did) disappear?
It's an emotive issue. It's also one of these things that is inconsistent not only across airlines but even with a given airline which suggests to me that when it happens it is crew initiated rather than airline policy otherwise I would expect that within a given airline a consistent policy would emerge.