Some bus shelters in Italy have supplies for this purpose.
This is not just a quick laugh; there's an important insight here about how customers perceive time. But no, I don't think it's a reason to tolerate lower frequencies ...
Robert Cervero: The Transit Metropolis: A Global Inquiry
A rigorous but readable study of the transit choices made by a range of cities around the world, and how these choices have shaped the city for better or worse.
David Sucher: City Comforts: How to Build an Urban Village, Revised Edition
Engaging book on the details of creating welcoming urban space.
Allan B. Jacobs: Great Streets
The definitive book on the ingredients of a great urban streetscape.