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.
I'll safe keep the private keys with me and allow it for 1.5yrs or 2yrs, if nobody had moved the coins in it, even a bit of it, I'll start using it for charity.
But while waiting for 1.5yrs or 2 and I discovered that someone is spending from the fund whose private keys I'm holding, I'll remain mute and calm and allow the person use their coins.
But I don't think it's possible to see a random private keys.