This is much easier to do than it might appear at first. A painter on his ladder may reach just an inch too fat to get into that corner and lose his balance. An electrician, careful and trained as he is, may not notice a thin puddle of leaking water that seeps beneath his feet as he handles “hot” wires. A manager in an apartment complex accidentally steps into a hole in the concrete, a hole left there by workmen getting to a water main. Perhaps they dutifully placed a cover or cone over the hole, but playing children moved it leaving a trap for the unsuspecting manager.