Applying “principle of least privilege” when it comes to execs and owners of the company – should they automatically get all permissions if requested?

As an administrator of certain systems in a company I understand and adhere to the “principle of least privilege” — which I’m assuming I don’t need to repeat its definition here, so let’s just say people here get given access to systems only in accordance with what they need for their role and no more. I follow that principle and check carefully whether they can have read-only access in order to carry out the role and if so I give read access only, etc.

I had a request from an executive-level (C-suite) person (“Jack”, let’s say) who is actually one of the five co-owners of the company, to get blanket “sysadmin” level access to a particular system. (I am confident the request has come from Jack himself and isn’t a hacking or phishing attempt, as I verified it with Jack directly.)

Jack is far too important and involved with strategic stuff to need to carry out any day-to-day work with this system, especially anything that would need sysadmin level access, but occasionally wants to get involved in “poking around” in there, as he is technical by background.

I get the sense that he doesn’t like the idea that he is “walled off” from some system although he owns part of the company.

I’m not asking about the interpersonal aspects about this, just the info-sec ones.

Is it accepted info-sec practice to give an owner of the company “sysadmin” access and by doing bypass the “principle of least privilege”? — since, after all, Jack (partly) owns the company so it’s all his stuff anyway!

Or should that still apply, and even the CEO shouldn’t have write-access to a system when they don’t need it as part of their job function?