The submitter of this item suggests that a new category ("D'oh!") be created for it (and others like it), and I'm seriously considering that.
In September, two men broke into a vacant building in Antioch, California, planning to steal copper wiring that they believed might still be inside. This is not as unusual as it might sound -- copper thefts are up nationwide because the value of copper has quintupled since 1999. For example, this article discusses a recent incident at a sandwich shop in Abilene, Texas, where thieves pulled the coils out of the air conditioning units, getting away with roughly $40 in copper. (The air conditioning units themselves were worth $3,000 each.)
So, in went our heroes, seeking the precious metal. This happened late on a Tuesday afternoon, which as it happens is right about the time that the Antioch Police Department's K-9 Unit runs training sessions at the same building. D'oh! Somebody didn't do his pre-theft research.
One of the men surrendered almost immediately, upon hearing an officer call out that a dog was about to be released into the building and that anyone inside should surrender or risk being attacked. It turned out this was part of the training. Another officer had hidden somewhere else in the 40,000-square-foot building and the dog was supposed to find him -- the officer outside was just following standard operating procedure. The men might not have been arrested at all had one of them not surrendered to a police officer who had no idea he was there.
Link: San Francisco Chronicle
