In Australia, it can take hours to drive between towns and fatigue can lead to accidents. So at busy holiday times rest stops are set up on major highways with volunteers offering free coffee. My wife, Merryn, and I grew to enjoy these stops during our long drives there.

On one trip, we pulled in and walked over to order our coffee. An attendant handed the two cups over, and then asked me for two dollars. I asked why. She pointed to the small print on the sign—at this stop, only the driver got free coffee; you had to pay for passengers.…