The batteries were the first thing I checked, and they are good. When the batteries are low in my luminara candles, they flicker and then quit.
Funny that you should mention ghosts in this thread...
...Because, the candles worked fine from July until the middle off November, when we brought into the house an antique filing cabinet purchased at the local antique mall. Seriously, we brought it into the house and I walked into the family room and the candle on my coffee table was on. It was off when we left the house to pick up the cabinet. Eeek!
Since then, sporadically, they have been turning themselves on. Now that everyone thinks I am crazy, I really do want to know a reasonable cause.