It is interesting we have almost the same examples about encryption I mostly agree with you, especially about EC and Contract. It seems that I did not do good work to explain my points. In abstracts style, they are:
1. Service execution context comprises conditions/circumstances
2. If a condition is not applied neither to the consumer nor to the provider, it unrelates to the consumer-provider interaction, i.e. it unrelates to the context (if a condition is applied to the communication media and does not affect communication parties it does not exist for them, i.e. it cannot be included in to the service description and service contract)
3. It seems that following relationship exists; description [multiple]contract(s) per description [multiple] execution context(s) per contract.
4. Though communication elements are very important, the communication context is not everything in the world besides consumer and provider themselves.
4. I certainly consider that not any condition IS a Policy (see my example of the Logging with encryption). But I say that any condition MAY be EXPRESSED as a Policy. With this instrumentation, I wrap all cases of conditions into the Policy format and put them into the contract; the subset of contracts conditions/policies constitute the context. This is it.
Sorry, it is too late for a coffee in London. But I wish a 'bonne apptit' to you, folks.