I do that, too. I don't like bright lights in the middle of the night, might ruin my sleeping when I'm back in the bed. However, when I'm sitting to the toilet in the dark, I'm making sure I'm sitting in the right place by my hand. Are you sitting down without "calibrating your position by hand" in the dark? Hoping your ass lands on the right spot? If you touch the toilet seat you will notice whether the seat is up or down.
How can you not notice?! I would literally need to close my eyes or enter the bathroom blindfolded to not see whether the seat is up or down.During the day, I may be distracted, cause again, I'm not expecting the toliet to be dirty and/or the seat to be up. Then again, my husband never leaves it disgusting and he always put the seats down for us, even in his own bathroom.