I have done it before, only at one place though, and it was years ago. I felt it was justified. I was told a certain hourly wage in my interview, turned out they were lying to me just to get me to work there instead of somewhere else. I noticed they were low balling me by a dollar an hour. I talked to them, got nowhere. No proof to take to the labor comission. So I immediately started looking for another job, while stealing food and equipment untill I felt it equaled the amount they owed me.
I know it wasnt right, but neither was what them lying to all of us. I got some good stuff too. Brand new stainless steel saute pans, entire tin of saffron, etc.I got out when my paycheck wouldnt clear for the third time. Went in that day, told them I quit, and collected unemployment for a few weeks. They tried to fight my unemployment claim but lost because they technicaly werent paying me for two weeks. Needless to say, they went under after a while.
If i busted somebody stealing, I would look at how my operation is running, and the morale of my staff. But sometimes people are just dirty theives for no reason. I probably wouldn't can them the first time, but definately dont ask me for any favors for a while.