Digital cash

Can someone explain to me how the system where double spending can reveal the identity of a user, but without double spending it is never discovered? I read the paper over and over, but I think a clearer explination would help. Thanks. Wonderer ------------------------------------------------------------------------- To find out more about the anon service, send mail to help@anon.penet.fi. Due to the double-blind, any mail replies to this message will be anonymized, and an anonymous id will be allocated automatically. You have been warned. Please report any problems, inappropriate use etc. to admin@anon.penet.fi.