So in the argument discussed in this topic, OP picking up a paper wallet worth 0.6btc, is this a theft scenario? because if we look at OP's story, he wants to return it to the real owner but he doesn't know how.
And I think it will be difficult to return it to the real owner because many opportunists will pretend that the paper wallet is theirs. Then for crypto enthusiasts, we know that Bitcoin is not fake money, because it can be converted into real money, not just touched physically.
What's the point of not taking the paper wallet in this scenario? If you don't take, someone else will take. At least, OP had a kind intention at first and that's so rare that it worth to bold it.
There are ways to prove the ownership. Maybe the owner had imported keys into his wallet and would be able to sign a message to prove the ownership or maybe he would be able to prove that it was his address in another way:
Imagine, you lost a wallet but you have sent coins there from your Binance account. Owner could prove that by letting the wallet holder to safely sign into his Binance account via qr code scan.
Okay, there are ways if we truly want.