to fit in the most you need the word protege or 323 on your car
Whether is a protege mp3, mazdaspeed protege, protege5, protege lx, protege es, or 323 or somethin.......you are fine.
You are equally welcome but just might not "fit in" as well if you simply have a mazda logo on your car, anywhere - even if its home made, like a piece of paper with the mazda logo written on it in pencil or crayon taped to the side of the car.
And last but not least, as evidenced by the audi, fords, and other makes that came to our Kent meet, even a mazda logo is not a requirment.
I guess the only requirment is that you are interested in proteges or mazdas of some kind.