> An object that has volatile-qualified type may be modified in ways unknown to the implementation or have other unknown side effects. Therefore any expression referring to such an object shall be evaluated strictly according to the rules of the abstract machine

The execution path has unknown side effects, and so the execution path must be strictly followed. That's uh... The entire point of that section in the C standard. Its why volatile is called out, in the semantic model for the abstract machine.

Otherwise... Why call it out, at all? It must be strictly followed, not lazily, as in other areas of the standard.