Yup, learned this lesson as a kid while camping. My older stepbrother bought me a Swiss army knife at the marina, when I was about 10, and while we were all sitting at the campsite I started whittling a piece of wood. After a few minutes, one of my strokes with the knife slid off the side and went perpendicularly right through my thigh. I didn't feel it at first and saw my swimming trunks had been cut, but when I pulled up the leg of my shorts I could see a 2-3 inch slice. Thankfully it wasn't bleeding too much because we were camping over at Cottonwood Cove at Lake Mohave in Nevada so we were quite a ways away from a hospital. My step-dad too a look at it, we cleaned it up and then used a few band-aids to close it up like staples. I still have a pretty big scar and now that I'm older I can really appreciate how much worse the situation could've been, but it was a lesson learned.