Finder's Keepers, Smartcards, Anon Cash [Re: double-spending prevention w. spent coins]

[Major Variola (ret)]

One of the attributes that a digital currency system MAY have is
whether someone who finds lost currency may spend it.   Conventional
cash has this property.  So do tickets to performances, lottery
tickets, bus tokens, prepaid phone cards etc..
A (tamper-resistant) smartcard may have this
'finders keepers' property, or may not.

A lost, signed-but-payee-blank check has the property that finders
can cash it, except if the (albeit stupid) loser goes "online" first.
(Maybe you need to buy a fake ID to cash it anonymously, but
its possible if its signed.)

Clearly the most anonymous systems (cash)
have the 'finders keepers' property, *necessarily*.

But one can imagine anonymous systems that are useless to finders,
e.g., a smartcard with a real PIN and/or fingerprint reader.  In these
cases, it is
advantageous to the finder to return the smartcard in hope of
a reward, IFF the loser makes this possible.

Maybe there's a bizmodel in being a clearing house for lost locked
smartcards,
without trashing their potential "bearer" anonymity unless
the loser tells the clearing house they've lost it.  Sort of like
calling
a prepaid ("debit") credit card house if you've lost it (assuming
prepaid credit card acceptance still requires going online) to
get a replacement.