Cross over at the front bumper, or into driveway at the back bumper?
Seems that you had a thrilling buzz of liberation. Could the woman have seen you if she looked up? If they can't see below waist down, they are none the wiser, guy with shirt off, and have doubts, and no recourse. If she saw naked, freaked and went for plates, with parking lot camera backup, there could be trouble, but still not so likely. Changing in a parking lot is not uncommon. Walking around nude is seen as a risk, or even intent (not just reckless) to walk around naked to be seen, instead of plain nudity. So, I suppose that you are looking for a danger/risk/personal dare buzz, too?
I don't think that I would do that. I'd stand behind an open door, or something more cautious. Potentially, let them know that I am changing, but not exposing genitals. But then again, my interpretation of what you wrote was you doing a risky behavior, that is that the woman could have looked up and seen you. I avoid hassles, but then I have enjoyed taking the trash out nude to expand the boundaries of my free naturist range.
If the woman took action, with plates, then there is the hassle of explaining to the officer who stops you down the road and assumes that he has nabbed an exhibitionist prevert, or explaining in court. So, was the woman potentially able to see that you were walking nude 12 feet in a Wally Mart Parking lot?
Jbee