Wow guys, easy on the consipiracy theories... For the record, I LUV my 370z.
I'm posting this specifically because it was sporadic (only happened once) and I saw someone post something similar before.
Here
Test Drive Gone Bad? is the posting that I remembered from a while ago.
Oddly enough, the previous poster mentioned a cutoff of 2500rpm, while mine was at 3500rpm.
I'll be keeping an eye on it, but previous poster had a really good idea: next time it happens, drive it straight over to the dealer and let them see it first hand. Might come down to something like that.
Thanks for all the input guys. I'll update if anything else happens.