Star is correct, Rojo is being obtuse. When you watch a marathon race on a record eligible course you never know how much of the 2-15 minute cushion over 2 hours is accounted for by race tactics, sub-optimal nutrition placement, adverse wind, awkward corners, hills etc. etc. In other words its impossible to know right now whether humans can run a perfectly staged but unassisted 1:59:59 (though I'm skeptical).
I am very confident the event Nike put on will be unassisted - it'll just focus on minimizing the detractions from ideal. It won't be materially downhill but it will be flat, it won't be wind assisted but it won't be windy, nutrition of any sort will be available at any time etc. etc. I'd bet on that.
In the unlikely event an event like that broke 2:00:00 I for one would consider it an incredibly meaningful data point. We now know humans can run that fast, the only question in any given race becomes why didn't they?
Not sure if it's been mentioned but Ed Auden is involved in this project so you know at least that the reporting will be top-notch.