Not to worry. There most likely will be around the clock security for the NSXs (don't quote me on this, but it's in the plans).
Besides, thieves won't make a lot of money off an NSX. It's too rare. They steal the most popular cars to chop up and sell for parts. The NSX would be way too obvious for them.
Where's LarryG's post predicting the theft?
I hope that everyone is always aware of their car security, no matter where they live. And I hope this will not be a deterrent to attending NSXPO, cause that would be just plain sad - to live in fear of a very small probability rather than enjoying your NSX, either with your fellow NSX owners at NSXPO or in general.
PS - Scottsdale (or Snottsdale) has some of the world's most expensive fine cars. If theft was such a big problem you would not see that many expensive cars there.
PPS - I'm also one of the most anal NSX owners out there when it comes to car security - I hardly let my NSX out of my sight, and I only let a very select few drive my NSX. I feel perfectly fine attending NSXPO with my NSX.