Question: If I picked up an identifiable stored value card on a bus, is it alright for me to use it, and donate its worth to charity on behalf of its owner?
Answer: This seems alright in principle. However, the owner might return to look for it, and especially if he or she is poor, the card might matter much. My suggestion is to pass it any driver of the same bus service number, if you have already left the bus. The driver can be the temporal custodian of it, in case any passenger asks for it.
The driver might bring it to the terminal office as a lost-and-found item later, and if so, so be it, as the owner might look for it there too. Putting it back to where it was found might make available for it to be found by the owner, but since there is a greater chance that it be picked up by someone else and not returned, passing it to the driver is the ‘Middle Path’.
Is Picking Up Lost Money Stealing?