I drive a Miata, and I leave the top down everywhere I go. I don't ever leave anything in the car, there's nothing valuable to steal, so it just sits. I leave the glove compartment unlocked, the center console unlocked.
Everyone asks me, "why do you leave the top down everywhere? Aren't you afraid of getting something stolen?" I just tell them I'd rather have them take the $5 of change in the cup holder rather than slash a top that I'd have to pay $400 to replace... And sometimes they don't bother to check the door handles before they slash the top... retards.
-meaty