Ever gone out of town and came back to your microwave flashing 12:00? Yep, the power went, but for how long? Did the contents of your freezer thaw out and refreeze, damaging the food inside? Give yourself peace of mind by putting a baggie of ice into the freezer before you leave. If it still looks like ice cubes when you get back, then it's all good. If the ice has melted and refrozen into a piece of solid ice, you better reconsider the food inside.
I always forget to do this. I have come home to find a snowstorm had hit our home, though, and had to consult neighbors to find out how long the power was out, bleh.