Why would it be any skin off your nose what someone else runs their car on? 95 RON or 99 RON, so the car runs slightly higher compression and ideally runs more efficient on higher octane. It's not your car and probably wont make an ounce of difference to the longevity of the engine.Remember more octane doesnt give you more power and although the car is designed to run on Premium but in the case that a lower grade fuel is used it will pull ignition timing to prevent detonation. That will result in less power and less fuel economy but it won't damage it.
That comment was tongue in cheek, but I think there is plenty of evidence to suggest that running a Zed on 95 RON has a detrimental effect on engine life. Mark from Abbey posted the technical reasons a while ago and also had some pics of some pistons which hadn't been happy using 95 RON.
Can you image that, Nissan developing a car that blows up when using 'normal' fuel, to be proved wrong by a few guys on a forum.
Of course I believe you though, I wouldn't want to start a big debate about it!
I guess the US cars and Zeds in other country's where fuel is even lower than 95 RON must have been mapped differently. In fact IIRC most fuel, sorry 'Gas' stations in USA have a max of 91 RON!