I remember a caving trip I went on when in the longish entrance crawl I met two other people on their way out. The informed me that there had been a collapse and the way on was blocked. I naturally enough suggested they showed me the "collapse" just on the off-chance they'd in fact taken a wrong turn. Sure enough, they'd gone the wrong way so I suggested they came with me and I'd show them the route all the way into the cave proper, including a tricky section a bit later on where you have to work your way through some boulders. This done, I went off exploring. I did then wonder if I'd been wise, given they'd already gone wrong in the first 50 yards, and I'd now I'd taken them well into a cave they didn't know and abandoned them !
A few hours later I was back at the tricky crawling through boulders bit and I met them again. They were actually going back into the cave but thought they were on their way out having done some kind of loop the loop in the boulders. Lucky I met them or they'd still be going round and round I expect