no...this theory is totally wrong.
they switch off unecessary light, to reduce consumption during take off, and by "unloading" the engine, it results to a shorter take off, better climb...
if an engine fail, you want be sure that all eletric load go to the cockpit for the pilot instruments, and not to unecessary lights in the PAX cabin.
for the window blind story , the palne as been crash cetified with window blind open...If they want keep the window closed, they will probably need an authorisation, resulting in more tests,...
gosh , where did you learn to fly? in a class room in front of you ATPL binders
???get a clue!!!