[kmak]

This was mentioned in "Predictably Irrational", essentially, this is exactly what you don't want to do, changing a decision from social to being economical. Unfortunately, you can't change it back easily.

I believe the example given was that of a daycare center. It used to be looked down upon when you pick up your kids late, and parents try to avoid it as much as possible. The center then added a penalty of some small monetary amount. This allows the parents to rationalize this as an economic decision, and many more chose to pay the fine. Even after they took the fine out again, they were unable to get the lateness rate down.