That's something I'm always concerned about, too. We do our neighborhood walk everyday, sometimes after dark. We use a flashlight but that doesn't really make everything clear, especially this time of year with all the leaves on the ground. Most residents here are good about bagging their dogs' poop but there are two problem situations. One, is the corners of each street that we cross (there are several). The sidewalks don't go to the end of each corner, so we walk on grass to cross the streets. For some weird reason, there is dog poop on the grassy corners, which, of course, is harder to see than on the pavement. The second problem is dogs who poop while walking behind their owners. It's usually Labs, who can poop without breaking stride; they don't slow down or squat. If they're walking behind their humans, the humans aren't aware of what happened. I know because our male Lab used to do the same thing. Fortunately, when we used to walk him we took a route that went out and then straight back, and we knew what he did, so we could spot his trail of deposits and pick them up. Yes, I know we could have made sure that he walked in front of us but then we would have stepped in his huge poops as they shot out. He was pooping machine.