My quibble was the use of the word "automatic".  This suggests, to me, something that happens without human intervention, which surely cannot be the case.  A visa cannot issue itself, law or no law.  The system that issues visas must be informed of the visit of the royal personage, and that information can only be provided by a human.  Effectively, someone, somewhere, has to decide to approve the issuing of this visa, and after that the system does what it needs to do.  To cause such a visa to be denied might be unprecedented and unthinkable, but surely someone, somewhere, has such a hypothetical power.  That it may never be used still does not make the issuing of the visa "automatic", in my understanding of the word.