I must admit Norm, that does sound surprising. Perhaps it is due to some agreement between the girls to stop the fouling - so seeing their name on the board may force them to confront their error in a way that motivates them to get it under control.
And honestly, in a practice situation what else can you do? Have them sit out practice? What good would that do? Generally any kind of physical punishment (even like running the arena steps) is discouraged in today's society. So perhaps with the commitment they have made to each other this works better. Sherri is a very smart coach, so I will give her the benefit of the doubt on this one.