RE: Security Question

I'm with Mark and Roger on this: 
> making the meaning of a message depend on something 
> external to a message is a bad idea for lots of reasons.

In the prototypical purchase order situation,
people seem to forget that an order is a legal contract.  

As ISO says, you're not just exchanging data,
you're exchanging business commitments.

Every message exchanged is evidence.
So are all the related schemas and metadata.

Ambiguity = more money for lawyers.

-Bob Haugen