Only if she advertised it somehow. The dick version is, of course, to tell the class that “you know, until now, if you had come in to challenge your grade I would have let you fix it. Too late now!”

Except they did not learned to not be shy. There was no such lesson. This is like saying that stealing from a student is ok, because it is teaching them thieves exist.

They learned that cheating gives advantage to the cheating individual. They also learned that reporting cheating harms them and non cheaters.