Your dad sounds way too paranoid of everything. >__>
My favorite restaurant is almost always full up when I go, so I park in the lot about, as you said, a half block away. Does your car not have locks on it or something? To me, it'd be a lot more of a hassle continuously checking on your car instead of simply walking a block total and being able to fully enjoy your meal.
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Xbox GT/PSN name: TatteredUniform
http://www.scuffletown.org/wp-content/uploads/2010/05/tRBE1.gif