Gas siphoning has most likely been a problem since the internal combustion engine was invented, but with gas prices the way they are, it looks like it's becoming an extreme problem.
My neighbor, who is foreman for a local construction firm, told me that he showed up for work the other day only to find that all the fuel had been siphoned out of their equipment. He said by the time he had refueled all of the equipment it cost him over $1,000, not including the cost of paying six employees to sit around until they could refuel.
Apparently organized crime is now getting into the game. Check out this story out of Florida.