All our eggs in one basket?

[Eric Hughes]

>If I failed to reply with a signed receipt, the bank could invalidate the  
>digital coin.  

Unfortunately for this idea, when the bank uses a blind signature to
issue coins, it doesn't know what coin it just issued actually looks
like.  The bank signs a blinded form of the coin.  The blinded form is
unblinded by the withdrawer, and the bank cannot know what it looks
like.

Eric