Planning. These things have got to be planned, thought through, down to the last detail. Take your jewel thief: he doesnt just walk into tiffanys and start filling his pockets with rocks, like Virignia Woolf
Not to worry. Certain members of the Living Nativity in front of the First National Bank of Pound Ridge (N.Y.) have definite plans for the several hundred thousand dollars in cash sitting inside the bank on Christmas Eve. They plan on taking it and yes, they have considered everything down to the last detail.
Then again, you can never entirely predict the human factor.