Two years ago, I pointed to a Britt Blaser post (which linked to Roland, who was linking to the source, Jason Kottke, whew!) about a donut vendor in NYC who put his customers on the honor system, and in the process doubled his customers per minute (as compared to other, similar donut vendors).
Having recently read Freakonomics, this struck me as somewhat similar to the bagel guy they profiled in Chapter One. (You can read at least a couple pages talking about Paul Feldman, the bagel guy, here. Oops. Nope, apparently you can’t link to searches inside the book; just go to the link above, and then search for Feldman.)
I’d love to see Levitt and Dubner look into this on their blog.