It would benefit you to stop being so myopic. Every public appearance of this car, scheduled or not, planned or not, has everything to do with marketing the brand. The Brand.. not just the product. A halo car has always been traditionally about marketing the brand probably even more so than marketing the specific car itself.
Of course, they are also using this opportunities to test the car. Hell, they will be "testing" the car even thru the first year it's sold to the public.
It would benefit you to actually think. I am actually giving Honda the benefit of the doubt. Obviously, there is marketing involved. But if you think this is primarily a marketing effort, then you obviously think very little of Honda.
So, let me get this straight. Honda wants to market this vehicle, so they:
1. Don't alert the press.
2. Don't announce scheduled showings so potential customers can get a chance to see the car.
3. Bring along some obviously preproduction cars, and not even bother to attempt to align the body panels, nor bring a car with what will likely be the up-optioned interior. Thereby showing the car in the worst possible light.
4. Show up unannounced at some random spot, just to get the opinion of some random passerby who will most likely not be a potential customer, rather than get the opinion of potential customers.
5. Not have the final specs, or the actual price available.
If you believe all this, then you must believe that Honda has the most inept marketing department in the world.
The more likely alternative:
Honda is a car company, that makes great cars. Furthermore, what made the original NSX so great was that it was, first and foremost, a supercar that actually worked and not just style and branding over substance like some of their competitors. So, in order to make this car worthy of the NSX name, they must ensure that the car is as fully sorted out as possible, which means extensive testing. Therefore, they will have to test these cars extensively on public roads in all sorts of environments. Sure, this is also an opportunity for the public to see the car, and some marketing effort is put into it. But the exercise is primarily for development of the car. Therefore:
1. There is no need to alert the press.
2. These are still being tuned, so no need for pristine and polished vehicles.
3. While there may be a planned route, the primary goal is development rather than showing off the vehicle. Therefore there is no way to schedule or announce any showings since issues may come up.
4. Final specs are still up in the air.
Now to me, one of these scenarios makes more sense than the other. I'm not saying that Honda hasn't made mistakes in the past, but I will give them the benefit of the doubt and believe that they are concentrating on substance over marketing.