Having read this entire thread, I am struck by the number of people who carry crap into the bush and leave it there. I am also always shocked by the mentality that says we should shoot it!! I have come across many things that were shot up, simply because they were there? That's pretty infantile, IMO. That's the same mentality that taggers and vandals have. Aren't we better than that?
Also, there are things "lost" that the owners intend to come back for and we have simply taken them? And kept them? I have left everything I have found in the woods for a decent period of time before I went back to check and see if they were still there. If so, then I would pick it up. I'd be pissed if a knife fell out of my belt when I was taking a dump, retraced my trail once I'd realized where I might have lost it, come back to find it gone and someone else's tracks all over the place. Might be tempted to track them...