Its not that only People can be lost but more often, things or our belongings may also be lost. Or maybe you were the one who have found belongings of other people. If the owner would be lucky enough to have left something that would identify them as the owner of the lost and found thing (like having their name, or address on it; leaving an ID etc.) there would be higher chances of getting their belongings back - let alone the honesty of the one who have found it.
If on the other hand, there is a name written on it but no address or contact details, it would be more difficult to find the real owner and most probably, they would not just think of pursuing to find the owner but rather let the owner come to them by announcing that they have found something.
Now let's say a person (or more than one person) comes up to you claiming that they were the owner of the thing you have found, how can you be able to know which of them are telling the truth? What you can do its maybe ask them for some information than can associate or identify them as the owner of the thing. If on the other hand you're still in doubt, you may try to look up and check the information that they tell you whether it is true. This way you will know that you will be returning the thing to the real owner.