I think most of us can agree that taking the Bitcoin is morally wrong. However, what I'm most interested in here is what would you guys do. Leaving it there, knowing that someone probably hasn't left it there by choice, means that leaving it there you're probably allowing someone else to pick it up, and steal it. Although, by taking it (and not redeeming it) you're basically not allowing the person that have lost it to retrieve it.

However, it's also a beach, and therefore I'm assuming that the tides would end up destroying the paper at some point. Handing it to police as some have hinted too, could be problematic too, you don't know they won't just disregard it as they aren't familiar with the way Bitcoin is backed up, but you also don't know if they're going to try to steal it themselves.

So, the moral stand point is if you know you are not going to redeem it, that's the only concrete information you have, everything else is chance. So, would taking the paper wallet, and then leaving a note of some kind for the original owner to contact you help? Then, the problem is you've now got the issue of identifying the true owner. Of course, you could be vague in the note that you leave, and that might be a way of going about it. However, what about a person that had already seen the paper wallet, not picked it up at the time, but upon research discovered its a paper wallet, and then returned for it, and could have enough information to convince you they were the original owner.

I don't know what's the answer to this, and it might be best to just leave it there. However, that proposes additional issues as well right? It's a bit like the moral dilemma of the train tracks, where doing nothing has consequences, but also doing something also has consequences.