In the two weeks that I have had my Z, I have not seen another 370. I have however seen many 350's and even a 280zx. Every time I give a little wave. Not once has it been reciprocated. You could argue that maybe they didn't see me but some were looking directly at me.
I remember, as a kid, when driving with my father in his 1970 240z, every other z we passed would wave. (That's my dad racing his 240z back in 1975 in my avatar)
So if you happen to be driving around Indianapolis and you see someone in a Monterey Blue 370Z give you a wave, throw one back.