[brucepick]

I'm sure there's a fair bit of this going on:

Three people at work, coming back from lunch, noticed my car with the "48 MPG" sticker on the window and the aero rear deck spoiler that was on at the time. So I answered their questions and told them what I was up to, and yes, I really was getting 48 mpg at the time (now 50+).

I learned that one of them was commuting over an hour in some big SUV.
Next thing I knew, she'd traded it for a Civic and is now happily getting 38 mpg. She was very pleased that she drove to Georgia (and back?) from CT for $120 gas cost.