This gesture probably goes unnoticed by the majority of common car drivers, but is quickly spotted by eagle-eyed Vette drivers. A few drivers who like audio reinforcement toot their horns to say hello to other Vettes they pass. This is acceptable, but risky. After all, when I'm driving along, my radio is usually cranked up to such a volume that I usually can't hear the horn beep. I could feel snubbed by a driver who only toots.
Convertible drivers are generally an enthusiastic group.
I've passed other convertibles on the highway and seen both the driver and passenger flailing their arms to catch my attention across six lanes. A little dangerous at highway speeds, but nonetheless, the greeting was appreciated and returned in kind. Many Vette owners selectively greet others. Since I drive a 70's vintage Vette, I've been snubbed by 60's drivers as well as 80's drivers. At first I was deeply hurt and offended.