e$ as "travellers check?

[Jonathan Rochkind <jrochkin@cs.oberlin.edu>]

There has been all this talk about potential legal problems with banks
issuing ecash. Lots of terms have been tossed around which I only
bearly understand like "bearer bonds" and such. And some things I
understand more, like the prohibition on private scrip. 
 
But someone a long time ago brought up traveller's checks, and the similarity
between them and ecash. The similarity seems pretty darn close to me. 
You pay some money to American Express, you get a note issued by them, you
give it to a merchant, he redeems in with AE for money. There's a fee charged
somewhere along the line. Well, you pay some money to First Digital Bank, you
basically get an electronic promissary note, you give it to a merchant for
a service or product, and he redeems it with First Digital for US dollars. 
 
I dont' know much about economics, but as far as I can tell this seems a pretty
solid analogy. If I'm missing something, can someone try to explain to me
using small words what it is I'm missing. Otherwise, what regulation is there
of people who issue traveller's checks? It's clearly not _illegal_ to issue
travellers checks, so I dont' see why it would be illegal under current laws
to issue ecash, despite all the interesting talk about bearer bonds and
private issued scrip. But perhaps there is strict regulation or something?