The documentary "Carts of Darkness" follows the exploits of a group of hotheaded homeless guys whose favorite pastime is to go bombing down the hills of North Vancouver, British Columbia, on shopping carts. Dangerous, subversive and incredibly fun, this is the kind of low-tech, no-rent extreme sport that your cart can be subjected to if you don't take the extra few seconds to bring it back to its station when you're done using it. Carts are designed to trundle placidly over polished tiles; they're not made to clock high velocity runs that include underhanded racing shenanigans worthy of "Ben-Hur." The carts in question have a short shelf life. Suffice it to say, there are no pit stops in the world of cart-racing.
Less spectacularly, if you leave your cart in the middle of a parking lot on the theory that some poor store employee will be forced to retrieve it, you're right — one of them will. But in the meantime, you're adding more clutter to the already difficult terrain of the parking lot. Also, you're increasing the odds that it'll get stolen by a joyrider. Don't let it become another cart of darkness.