As usual, Massad is spot on with his advice. The key to all of this is to make it a habit so that even when you are not actively thinking about your awareness it will be set up to work for, not against you.
A point not made in the video but even more common than the ambush, is a car simply pulling out into your path because the driver did not see you. It is always a good idea to scan the interiors of all the cars you are approaching to be aware of possible problems.
I like the idea of dropping one's keys to appear casual.
BTW, while you are down there checking under the cars, look for cans, bottles, nails, packages, anything that may be about to get run over by your tires.