Many years ago, I had to pick up a package from the local UPS distribution center. This was back in the old days, before everybody had a GPS with turn-by-turn navigation. In the uphill-both-ways era, the way you figured out how to get somewhere was to pull out a map printed on paper and plot your strategy unassisted.
Armed with my homemade directions to the UPS distribution center, a granola bar, and a signal flare to assist search-and-rescue in locating me, I set out on my quest.
As luck would have it, I chose to set out on my journey early in the morning, just as the UPS trucks arose from their slumber and set out in search of food, or whatever it is they do in the morning. As I got within a few miles of the distribution center, I saw a stream of brown trucks coming toward me.
"What luck!" I thought to myself, nibbling on a granola bar. I don't need to consult the directions I scribbled down. I can just follow the UPS trucks back to their lair!
This plan worked great. The convoy of UPS trucks continued without a break, allowing me to trace their path backward, like a schoolboy following an ant trail.
Or at least the plan worked great until I reached the source: The UPS loading dock and a gate with the sign Authorized vehicles only.
(I managed to find the customer entrance by going around the block. So this plan sort-of worked after all.)