Last week, I was on my way home from Ann Arbor when I stopped at a gas station just off the highway to fill up my car.  As the pump was cheerfully listing local bankruptcy attorneys (hey, it could happen), my gaze wandered, and for the first time, I noticed the odd set of signs posted at the entrance.  The side facing the road has an unremarkable sign directing cars to the pumps, but the side facing the pumps … well, I guess you can check out any time you like, but you can never leave.