Sure, but if I had heard several news reports of people finding and returning wallets being falsely accused of theft and subjected to serious legal threats, at that point if I saw someone's wallet lying around, I would just ignore it and keep going.
The bug bounty isn't only about the money. It's also the company's way of advertising 'we aren't crazy assholes like those outfits you heard about on the news'.
(Yes, fixing the law would be a good idea. But in the meantime, a bug bounty is the solution.)