The main difference between Cigs and Where's Trolley is that graffiti doesn't move.

But they both have similarities in that you kind of sense where you're likely to find your quarry. For trolleys, there's always something around here. It's about 1/3 of a mile from the Morrisons from where the trolley has been taken, and before you get into the housing proper. So you've carted the shopping most of the way home, but not incriminated yourself by leaving it in your front garden or driveway.