I think it would be alright to do, but don't expect everyone to join in. Corvette owners do it, but not all. I've received hands waving out of the top to indifferent stares and total indifference as I passed other vettes. Most raise a couple fingers off the steering wheel if they give you anything at all, but at least it's not one raised finger.
It got to the point that I would wait for them to wave first because returned waves got so scarce.
I'll go along with the forum, what say ye guys and gals, should we wave?
P. S. The best was the "beep beep" from Roadrunner to Roadrunner, and almost everyone returned the "beep beep".