In the mall area; if a car even remotely smells fishy (and I do mean "smell") that car would be immediately pulled over and torn to pieces on the spot. You park it in any of the normal tourist parking areas on the mall and it would be torn apart even quicker than immediately. If it's high tech and ridiculously expensive; then that tech will be on the mall on the ellipse and at the puzzle palace.
So, if you do come to DC, please. Take LOTS of pictures in the touristy areas. Never know what you might see on those pictures.