Yes I think we all know that the Captain has "the authority" as opposed to "the ownership" a point seemingly lost on the subject of my response, and a point which you yourself have repeated !
A Commanders authority is in part to comply with and uphold the relevant rules and regulations other than in a situation where there might be compelling reasons not to. Those compelling reasons do not extend to simply satisfying the Commanders opinions, prejudices or moods on any given day. There might indeed be compelling reasons why an unauthorized person is permitted, however such a "compelling reason" is unlikely to extend to the suggestion that it is simply someone you know to whom you wish to extend an otherwise unlawful invitation. Captains are normally appointed for their demonstrated maturity, judgement and common sense in addition to the more technical requirements. If they fail to display such attributes on the line it is a position they are probably unlikely to hold on to.
Like many other jobs an aircraft commander is a team leader who leads by example and good management, not by pointing at their gold bars and saying "I am master of all I survey and I alone will decide which rules apply to me".
I only have 18 years of commanding large aircraft under my belt, and it seems the more experience I aquire in the role the more I need to learn. However I have certainly witnessed the foolishness of those who simply ignore the rules they are required to comply with, because those rules do not suit their own whims or beliefs. In this example (you say) these rules do not apply in your company or country (yet ?) and therefore it is not particularly relevant to you, other than if you are flying into countries such as the USA or the UK where you are required to comply. I have grave doubts that any reported transgressions of the rules would meet with the appropriate authorities gleeful understanding that your perceived "authority" superceded their own ? Perhaps your own command experience (?) gives rise to an alternative viewpoint ?
Maybe now you have a better insight into my understanding of a commanders authority and as important, obligations ?