What would you do if you managed to come across someone else's private key and it's worth an amount that most people would 'prefer not to lose', assuming you have no [idea who it belongs] to or [location clues]? Eg. Sweeping through common books' text for BIP39-based keys.
I suppose you could send a dollar's worth to a different address and hopefully they'd get the hint.
Is there a particular amount of money that some people would actually prefer to lose? I dont know about you, but I would prefer not to lose any of my money.
Since were all assuming, Ill assume youre not asking if its okay to steal someones coins just cause you happen to come across it.
Yes; they'd not want to lose it.
Yes; you'd not want to steal it, but would feel awkward having discovered that their valuable key isn't safe.