"Work Experience," by Simon Brett, in Ellery Queen's Mystery Magazine, September/October 2011.
We're back in dumb criminal territory here. What else can you say about thieves who take a school-aged nephew along on a heist, a sort of take-a-teen-to-work program? The reason Brett's story stood out from the pack is a surprise ending that made perfect sense but which I didn't see coming at all. A lot of fun.