I'm just finishing up a few weeks of good travel through Cambodia and wanted to pass on a warning to all you other laptop wielders.
Earlier in the trip I met a guy who had been using his laptop in a WiFi-enabled shopfront bar/restaurant, he got up and walked back to the bar about 2-3 metres away to order a coffee, heard a smash and his laptop was gone! Some urchin streetside had been eye-balling him and as soon as he was out of his seat this kid bolted over, grabbed it and ran. The guy insisted his back wasn't turned for more than a few seconds. Never saw his laptop again.
Since then, I've been asking around and heard a few similar stories, more often than not the laptop is dropped or damaged either in the act as they try to grab it (especially if its plugged in), or during the chase when they chuck it to the ground in order to get away. I wouldn't say it's overly common, but it seems it is a growing problem.
I'm safely hidden away upstairs at Phnom Penh's FCC as I type, so I'm outa reach, but certainly something to keep in mind if you're thinking of working away streetside.