I do a lot of shopping at the Aldi's near my house. When it was just Adam and I, and I was desperately poor, the place was a life-saver; I'd spend less than half of what I'd spend at another grocery store.
I usually cut through an alley to save a few steps. I pass by the back of a building that for years was a neighborhood eyesore, but has been recently renovated, including the electrical works. In the alley, there are the fixtures for future electrical meters. Since they haven't sold any of the units in the building, they haven't installed any of the meters. So they covered the openings with cardboard.
You'll notice that the contractor took care to mark the cardboard-covered meters as "Hot." For those of you whose fathers weren't electricians or haven't done electrical work themselves (guilty as charged in both cases), "Hot" is electrician-speak for something that is electrically active. The boxes, which stand about chest-high, have juice running through them.
But hey, I'm sure it's UL-listed cardboard.