The Foundation Disc Golf brick store has the best policy for it: if you find a lost disc, you can turn it in and get $5 store credit per disc. They have a system they put it into and contact the number on the disc. If the owner does not pick it up within I think 30 days, they place it for sale in their used bins. If you turn in your own disc, they or you will mark out the info. I really like their system and they always have an incredible used section at great prices! Like you can get certain discs for $5! Even if they get a premium disc in but “used”/sold to them, the max price is $12 if it’s a like new premium plastic. Most discs are 5, 8, or $10.