Wikipedia says:
Denver International Airport uses many pneumatic tube systems, including a 25 cm diameter system for moving aircraft parts to remote concourses, a 10 cm system for United Airlines ticketing, and a robust system in the parking toll collection system with an outlet at every booth.
Problem: No citation, and I can't find any reference to it on the web.
My question: Would it be acceptable to post a question asking about this system's size and usage rate, even though I am not sure it actually exists?
UPDATE: Seeing the consensus, I proceeded to post the question.