Popcornbird, you are right to be concerned. Everyone needs to be aware of how important this is, hopefully without becoming an obscessive compulsive. My husband has occasionally left the burner on and I discover it. I told him that I make it a routine to turn the burner off before serving anything out of a pan or removing the pan from the stove. Same goes with the oven. First turn it off, then take out the brownies! The idea of a sign is a good one too. As I get older, I have to force myself to focus on the task at hand. I tend to make mistakes like this (yes, I've done it too) when I'm thinking about something else while doing such chores. Multitasking was a breeze when I was younger, but as I age, I realize it can be distracting.