Theft is unpreventable in many ways -- if they want it bad enough, they're coming in. But taking a man's laptop, that's just damn wrong.
I learned this harsh lesson via a bad storm back in 1992. I had spent the summer preparing for a new position teaching statistics at Indiana University when the day before classes started a massive electrical storm blew out the transformer at my cheap apartment and lightning struck the building, burning out all the wall sockets, and subsequently frying my bright new ($4200) PC! I spent the entire year working from behind and without a computer of my own, it was nearly impossible to do my job. I even had replacement insurance (along with a special rider) on that very machine, but when I went to my agent, he said: "Sure, get three estimates to average the cost of replacing your PC, you replace the machine, bring us the receipts, and we'll reimburse you in six months." I was broke, couldn't afford to do that, and PC-less for a year.
Mind you, I've never spend another GD nickel on insurance since that day!