Geordie: the problem is that we don’t know. Sometimes the owner can’t come back right away and it gets blown away or ruined from the elements. Or it gets stolen. There are some lost and find hotlines but it’s not streamlined or people forget to call.
I don’t know what the answer is either, but in the past when I hung something someone lost in front of my house on my front yard fence (a belt etc.) it stayed there for weeks until I just dumped it. Some things are less valuable so people don’t bother or they have no clue where they lost it.