After reading the 'simple overview' I have exactly the same questions as you. It's all nice that the contract runs and checks for conditions and such ... howeve

After reading the 'simple overview' I have exactly the same questions as you. It's all nice that the contract runs and checks for conditions and such ... however the 'implementation' of the condition checking seem to be the Achilles heal of this whole thing. For example, the use-case of the online buyer, who would check the phone was shipped? Another 'smart-contract' ...?