this is a good question - especially in light of the recent post about the keyed lexus at south coast - the prob is that some people just can't stand that other people have something nice and look at you leaving the top down as a "rub" or that you're dangling your stuff for the world to envy.
i actually had the last two days off and enjoyed some sunny soCal weather with the top down, taking care of errands etc and found myself challenged with what to when "popping in here, popping in there". I agree with EpiqTodd (til something happens to my car - but then again - its black - I spaz about a frickin piece of debris on it 5 sec after I wash it!) - I've never liked the people who park way at back of the lot, crooked in two spots (that in my opinion, just invites someone to f$%k with your car). I actually left the top down most of the time over the last few days, except for when I was in a place for a couple of hours - hell, birds don't have a ton of discretion!
on wednesday, i came out of a restaurant after lunch to find a guy driving an older 300z walking around my car, looking in the windows, squatting down, looking at the tires. His back was to me the entire time as i approached. Since I didn't see anyone else doing look out for him, I continued to approach. I got close enough and hit the unlock button, thinking maybe the sound would alert him that I was approaching - the whole time I was contemplating how to engage him - was he just admiring the car or casing the car (he was in his mid 20's - loose baggy pants, loud stereo - okay, gotta forgive that one - i love it loud (what? a KISS reference?) - anyway, so I'm thinking, do I throw out, in an intimidating tone 'something I can help you with' and go the dickhead route or do I play it nice at first a see where this goes ? Well, unlocking the car didn't grab his attention, so as i got right up to the car and he's down looking at the wheels, I say "it's nice, isn't it?" (i got burned once in my early 20's checking out some older guys wife in a restaurant - didn't see him as I was watching her walk through the restaurant - he comes up and says, she's nice isn't she?") So, turns out this guys was just admiring the car, so the decision to be civil and neighborly was appropriate. Top wasn't down that time, though. Top wasn't down on the guy's wife, either
Hybrid Mode
