As our 'just under OSHA's safe hearing limits' subway hummed to a stop, I felt a gentle nudge at my left side. Turning to find a kind but concerned looking fellow passenger, I raised my eyebrows quizzically. She pointed at the kids. "Ah," I thought, "she's about to comment on how awesome the kids are!" It was the obvious answer, but why did she look so concerned? She leaned in conspiratorially. "Their shoes might be on the wrong feet," she whispered. "Hunh, would you look at that? Cool! Thanks!" I replied with a big grin. Off the train went roaring through the tunnels of San Francisco again. At the next station, the train doors slid open letting the bright platform lights flood in. I felt another nudge. This time my fellow passenger leaned back in contemplation, staring at the kids' shoes. For fun, I leaned back with her. We studied the footwear in question in some detail. She nodded her head, then lea...